keystone2: env: Set mmc as default boot for k2g-evm

For k2l, k2e and k2hk, ubi is set to default boot in uboot
environment settings; while for k2g, mmc should be the
default boot. This patch is to set mmc as default for k2g-evm

Signed-off-by: Yan Liu <yan-liu@ti.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/include/configs/k2g_evm.h b/include/configs/k2g_evm.h
index 2e47763..7bc506f 100644
--- a/include/configs/k2g_evm.h
+++ b/include/configs/k2g_evm.h
@@ -18,6 +18,7 @@
 #define CONFIG_EXTRA_ENV_KS2_BOARD_SETTINGS				\
 	DEFAULT_MMC_TI_ARGS						\
 	DEFAULT_PMMC_BOOT_ENV						\
+	"boot=mmc\0"							\
 	"console=ttyS0,115200n8\0"					\
 	"bootpart=0:2\0"						\
 	"bootdir=/boot\0"						\