da850/omap-l138: Add support to read u-boot image from MMC/SD

DA850/OMAP-L138 does not support strict MMC/SD boot mode. SPL will
be in SPI flash and U-Boot image will be in MMC/SD card. SPL will
do the low level initialization and then loads the u-boot image
from MMC/SD card.

Define CONFIG_SPL_MMC_LOAD macro in the DA850/OMAP-L138
configuration file to enable this feature.

Tested-by: Christian Riesch <christian.riesch@omicron.at>
Signed-off-by: Lad, Prabhakar <prabhakar.lad@ti.com>
Signed-off-by: Rajashekhara, Sudhakar <sudhakar.raj@ti.com>
Signed-off-by: Hadli, Manjunath <manjunath.hadli@ti.com>
diff --git a/drivers/mmc/Makefile b/drivers/mmc/Makefile
index c567737..2b96cdc 100644
--- a/drivers/mmc/Makefile
+++ b/drivers/mmc/Makefile
@@ -25,6 +25,10 @@
 
 LIB	:= $(obj)libmmc.o
 
+ifdef CONFIG_SPL_MMC_LOAD
+COBJS-$(CONFIG_SPL_MMC_LOAD)	+= spl_mmc_load.o
+endif
+
 COBJS-$(CONFIG_BFIN_SDH) += bfin_sdh.o
 COBJS-$(CONFIG_DAVINCI_MMC) += davinci_mmc.o
 COBJS-$(CONFIG_FSL_ESDHC) += fsl_esdhc.o