请问系统怎样彻底去掉SD和MMC电路呢

我的系统不需要SD卡和MMC卡支持，这部分电路去掉了，但启动会报告以下信息：[    9.130137] *mmc1 detect cd change*
[    9.133958] *mmc1 lock*
[    9.136644] sunxi-mmc 1c0f000.sdmmc: sdc set ios: clk 0Hz bm PP pm UP vdd 22 width 1 timing LEGACY(SDR12) dt B
[    9.160078] sunxi-mmc 1c0f000.sdmmc: sdc set ios: clk 400000Hz bm PP pm ON vdd 22 width 1 timing LEGACY(SDR12) dt B
[    9.190991] sunxi-mmc 1c0f000.sdmmc: smc 1 p0 err, cmd 52, RTO !!
[    9.198731] sunxi-mmc 1c0f000.sdmmc: smc 1 p0 err, cmd 52, RTO !!
[    9.205523] sunxi-mmc 1c0f000.sdmmc: sdc set ios: clk 400000Hz bm PP pm ON vdd 22 width 1 timing LEGACY(SDR12) dt B
[    9.219862] sunxi-mmc 1c0f000.sdmmc: sdc set ios: clk 400000Hz bm PP pm ON vdd 22 width 1 timing LEGACY(SDR12) dt B
[    9.233512] sunxi-mmc 1c0f000.sdmmc: smc 1 p0 err, cmd 8, RTO !!
[    9.241165] sunxi-mmc 1c0f000.sdmmc: smc 1 p0 err, cmd 5, RTO !!
[    9.248830] sunxi-mmc 1c0f000.sdmmc: smc 1 p0 err, cmd 5, RTO !!
[    9.256460] sunxi-mmc 1c0f000.sdmmc: smc 1 p0 err, cmd 5, RTO !!
[    9.264083] sunxi-mmc 1c0f000.sdmmc: smc 1 p0 err, cmd 5, RTO !!
[    9.271677] sunxi-mmc 1c0f000.sdmmc: smc 1 p0 err, cmd 55, RTO !!
[    9.279405] sunxi-mmc 1c0f000.sdmmc: smc 1 p0 err, cmd 55, RTO !!
[    9.287114] sunxi-mmc 1c0f000.sdmmc: smc 1 p0 err, cmd 55, RTO !!
[    9.294828] sunxi-mmc 1c0f000.sdmmc: smc 1 p0 err, cmd 55, RTO !!
[    9.301562] sunxi-mmc 1c0f000.sdmmc: sdc set ios: clk 400000Hz bm OD pm ON vdd 22 width 1 timing LEGACY(SDR12) dt B
[    9.314237] sunxi-mmc 1c0f000.sdmmc: smc 1 p0 err, cmd 1, RTO !!
[    9.320874] sunxi-mmc 1c0f000.sdmmc: sdc set ios: clk 0Hz bm OD pm OFF vdd 0 width 1 timing LEGACY(SDR12) dt B
[   10.320379] gpu cooling callback set freq limit 384
[   10.980052] *mmc3 detect cd change*
[   10.983890] *mmc3 lock*
[   10.986587] sunxi-mmc 1c12000.sdmmc: sdc set ios: clk 0Hz bm PP pm UP vdd 22 width 1 timing LEGACY(SDR12) dt B
[   11.010074] sunxi-mmc 1c12000.sdmmc: sdc set ios: clk 400000Hz bm PP pm ON vdd 22 width 1 timing LEGACY(SDR12) dt B
[   11.041052] sunxi-mmc 1c12000.sdmmc: smc 3 p3 err, cmd 52, RTO !!
[   11.048821] sunxi-mmc 1c12000.sdmmc: smc 3 p3 err, cmd 52, RTO !!
[   11.055586] sunxi-mmc 1c12000.sdmmc: sdc set ios: clk 400000Hz bm PP pm ON vdd 22 width 1 timing LEGACY(SDR12) dt B
[   11.069959] sunxi-mmc 1c12000.sdmmc: sdc set ios: clk 400000Hz bm PP pm ON vdd 22 width 1 timing LEGACY(SDR12) dt B
[   11.083549] sunxi-mmc 1c12000.sdmmc: smc 3 p3 err, cmd 8, RTO !!
[   11.091136] sunxi-mmc 1c12000.sdmmc: smc 3 p3 err, cmd 5, RTO !!
[   11.098763] sunxi-mmc 1c12000.sdmmc: smc 3 p3 err, cmd 5, RTO !!
[   11.106398] sunxi-mmc 1c12000.sdmmc: smc 3 p3 err, cmd 5, RTO !!
[   11.113983] sunxi-mmc 1c12000.sdmmc: smc 3 p3 err, cmd 5, RTO !!
[   11.121627] sunxi-mmc 1c12000.sdmmc: smc 3 p3 err, cmd 55, RTO !!
[   11.129354] sunxi-mmc 1c12000.sdmmc: smc 3 p3 err, cmd 55, RTO !!
[   11.137066] sunxi-mmc 1c12000.sdmmc: smc 3 p3 err, cmd 55, RTO !!
[   11.144795] sunxi-mmc 1c12000.sdmmc: smc 3 p3 err, cmd 55, RTO !!
[   11.151477] sunxi-mmc 1c12000.sdmmc: sdc set ios: clk 400000Hz bm OD pm ON vdd 22 width 1 timing LEGACY(SDR12) dt B
[   11.164135] sunxi-mmc 1c12000.sdmmc: smc 3 p3 err, cmd 1, RTO !!
[   11.170785] sunxi-mmc 1c12000.sdmmc: sdc set ios: clk 0Hz bm OD pm OFF vdd 0 width 1 timing LEGACY(SDR12) dt B

想把这些去掉，我注释了CONFIG_MMC，但编译出现以下错误：
drivers/built-in.o: In function `scan_device_store':
sunxi_dramfreq.c:(.text+0xb2d18): undefined reference to `sunxi_mmc_rescan_card'
make: *** [vmlinux] Error 1

搜索代码发现只要定义了CONFIG_ARCH_SUNXI=y，就会有好几个地方调用sunxi_mmc_rescan_card函数，难道要把
CONFIG_ARCH_SUNXI=y去掉吗？