[U-Boot] [PATCH v3] mx6qsabresd: Fix booting the kernel from SDHC3

[Fabio Estevam]

Since commit de7d02aeb (mx6qsabresd: add usdhc2 and usdhc4 support) 
SDHC3 device node is no longer 0, which breaks loading a uImage from SDHC3.

Fix it by adapting the default environment to use CONFIG_SYS_MMC_ENV_DEV as the 
correct mmc node for loading the kernel from.

While at it, go back to using SDHC3 as the default mmc, since we have Yocto 
images that generate an SD card containing U-boot,kernel and rootfs, so it is
more convenient to keep using SDHC3 as it was originally.

Signed-off-by: Fabio Estevam <fabio.estevam at freescale.com>
---
Changes since v2:
- Use __stringify to properly pass CONFIG_SYS_MMC_ENV_DEV
Changes since v1:
- Properly expand mmcdev macro
- Improve commit log
 include/configs/mx6qsabre_common.h |    2 +-
 include/configs/mx6qsabresd.h      |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/configs/mx6qsabre_common.h b/include/configs/mx6qsabre_common.h
index bd2fb10..95ebd98 100644
--- a/include/configs/mx6qsabre_common.h
+++ b/include/configs/mx6qsabre_common.h
@@ -86,7 +86,7 @@
 	"console=" CONFIG_CONSOLE_DEV "\0" \
 	"fdt_high=0xffffffff\0"	  \
 	"initrd_high=0xffffffff\0" \
-	"mmcdev=0\0" \
+	"mmcdev=" __stringify(CONFIG_SYS_MMC_ENV_DEV) "\0" \
 	"mmcpart=1\0" \
 	"mmcroot=" CONFIG_MMCROOT " rootwait rw\0" \
 	"mmcargs=setenv bootargs console=${console},${baudrate} " \
diff --git a/include/configs/mx6qsabresd.h b/include/configs/mx6qsabresd.h
index a1d9285..ccb7751 100644
--- a/include/configs/mx6qsabresd.h
+++ b/include/configs/mx6qsabresd.h
@@ -27,7 +27,7 @@
 
 #define CONFIG_SYS_FSL_USDHC_NUM	3
 #if defined(CONFIG_ENV_IS_IN_MMC)
-#define CONFIG_SYS_MMC_ENV_DEV		2	/* eMMC/uSDHC4 */
+#define CONFIG_SYS_MMC_ENV_DEV		1	/* SDHC3 */
 #define CONFIG_SYS_MMC_ENV_PART		1	/* Boot partition 1 */
 #endif
 
-- 
1.7.9.5