drivers/mmc: move spl_mmc.c to common/spl

The mpc85xx repuires a special layout on the memory device that is
connected to the eSDHC controller interface. But the file spl_mmc.c
didn't handle this specfic case, there needs a special treatmen, in
the powerpc drictory. So, there is no longer to keep spl_mmc.c on
mpc85xx, CONFIG_SPL_FRAMEWORK is not set.

When CONFIG_SPL_MMC_SUPPORT is set and CONFIG_SPL_FRAMEWORK is not
set, there was an error in drivers/mmc/spl_mmc.c:

drivers/mmc/libmmc.o:(.got2+0x8): undefined reference to `spl_image'.

Now, the solution is to move the file "spl_mmc.c" to directory "common/spl".
Signed-off-by: NYing Zhang <b40530@freescale.com>

common/spl/Makefile

@@ -20,6 +20,7 @@ COBJS-$(CONFIG_SPL_YMODEM_SUPPORT) += spl_ymodem.o
 COBJS-$(CONFIG_SPL_NAND_SUPPORT) += spl_nand.o
 COBJS-$(CONFIG_SPL_ONENAND_SUPPORT) += spl_onenand.o
 COBJS-$(CONFIG_SPL_NET_SUPPORT) += spl_net.o
+COBJS-$(CONFIG_SPL_MMC_SUPPORT) += spl_mmc.o
 endif
 
 COBJS	:= $(sort $(COBJS-y))

drivers/mmc/Makefile

@@ -25,9 +25,6 @@ include $(TOPDIR)/config.mk
 
 LIB	:= $(obj)libmmc.o
 
-ifdef CONFIG_SPL_BUILD
-COBJS-$(CONFIG_SPL_MMC_SUPPORT) += spl_mmc.o
-endif
 
 COBJS-$(CONFIG_BFIN_SDH) += bfin_sdh.o
 COBJS-$(CONFIG_DAVINCI_MMC) += davinci_mmc.o