omap5_uevm: Add CONFIG_SUPPORT_EMMC_BOOT, document usage

Add a README to the board which lists the commands required to enable
booting from the eMMC boot partitions found on the board.

Signed-off-by: Tom Rini <trini@ti.com>
Signed-off-by: Pantelis Antoniou <panto@antoniou-consulting.com>
diff --git a/include/configs/omap5_uevm.h b/include/configs/omap5_uevm.h
index 76c5106..3df502e 100644
--- a/include/configs/omap5_uevm.h
+++ b/include/configs/omap5_uevm.h
@@ -37,6 +37,7 @@
 #define CONFIG_PARTITION_UUIDS
 #define CONFIG_CMD_PART
 #define CONFIG_HSMMC2_8BIT
+#define CONFIG_SUPPORT_EMMC_BOOT
 
 /* Required support for the TCA642X GPIO we have on the uEVM */
 #define CONFIG_TCA642X