mx6sxsabresd: Load the correct dtb for revA board

Currently only imx6sx-sdb.dtb is loaded, but if revA board is used the
correct dtb is imx6sx-sdb-reva.dtb, so make this possible.

While at it, remove an extra 'mmc dev'.

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
diff --git a/configs/mx6sxsabresd_defconfig b/configs/mx6sxsabresd_defconfig
index a411032..b707322 100644
--- a/configs/mx6sxsabresd_defconfig
+++ b/configs/mx6sxsabresd_defconfig
@@ -2,6 +2,7 @@
 CONFIG_ARCH_MX6=y
 CONFIG_TARGET_MX6SXSABRESD=y
 # CONFIG_CMD_BMODE is not set
+CONFIG_NXP_BOARD_REVISION=y
 CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=board/freescale/mx6sxsabresd/imximage.cfg"
 # CONFIG_CONSOLE_MUX is not set
 CONFIG_SYS_CONSOLE_IS_IN_ENV=y
diff --git a/configs/mx6sxsabresd_spl_defconfig b/configs/mx6sxsabresd_spl_defconfig
index a0483c3..9ab4b2f 100644
--- a/configs/mx6sxsabresd_spl_defconfig
+++ b/configs/mx6sxsabresd_spl_defconfig
@@ -9,6 +9,7 @@
 CONFIG_SPL_LIBDISK_SUPPORT=y
 CONFIG_SPL_WATCHDOG_SUPPORT=y
 # CONFIG_CMD_BMODE is not set
+CONFIG_NXP_BOARD_REVISION=y
 CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=arch/arm/mach-imx/spl_sd.cfg"
 # CONFIG_CONSOLE_MUX is not set
 CONFIG_SYS_CONSOLE_IS_IN_ENV=y