imx: sksimx6_defconfig: remove SPL misc option to fix build error

Remove CONFIG_SPL_DRIVERS_MISC_SUPPORT since it is already defined
in include/configs/mx6_common.h for SPL builds. When this option
is in defconfig, we get build warnings (or errors when building
with -Werror).

Signed-off-by: Anatolij Gustschin <agust@denx.de>
diff --git a/configs/sksimx6_defconfig b/configs/sksimx6_defconfig
index 5fbc94a..d8739fd 100644
--- a/configs/sksimx6_defconfig
+++ b/configs/sksimx6_defconfig
@@ -8,7 +8,6 @@
 CONFIG_TARGET_SKSIMX6=y
 CONFIG_SPL_MMC_SUPPORT=y
 CONFIG_SPL_SERIAL_SUPPORT=y
-CONFIG_SPL_DRIVERS_MISC_SUPPORT=y
 CONFIG_NR_DRAM_BANKS=1
 CONFIG_SPL=y
 CONFIG_SPL_LIBDISK_SUPPORT=y