configs: enable spl support wrt env device

nand device needed for mmc config to access nand
for write and update so enabling SPL_SUPPORT to mmc
or nand is wrt to env device rather nand driver check.
Signed-off-by: NJagan Teki <jagan@amarulasolutions.com>

include/configs/imx6-engicam.h

@@ -208,7 +208,7 @@
 
 /* SPL */
 #ifdef CONFIG_SPL
-# ifdef CONFIG_NAND_MXS
+# ifdef CONFIG_ENV_IS_IN_NAND
 #  define CONFIG_SPL_NAND_SUPPORT
 # else
 #  define CONFIG_SPL_MMC_SUPPORT