mx6sabreauto: Add DM_GPIO support

Add the DM_GPIO related config for mx6sabreauto.
Also add the gpio request calls.

Signed-off-by: Abel Vesa <abel.vesa@nxp.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
diff --git a/configs/mx6sabreauto_defconfig b/configs/mx6sabreauto_defconfig
index d4a42f6..f692d1b 100644
--- a/configs/mx6sabreauto_defconfig
+++ b/configs/mx6sabreauto_defconfig
@@ -57,6 +57,7 @@
 CONFIG_SPL_DM=y
 CONFIG_DFU_MMC=y
 CONFIG_DFU_SF=y
+CONFIG_DM_GPIO=y
 CONFIG_DM_MMC=y
 CONFIG_FSL_ESDHC=y
 CONFIG_NAND=y