AM3517_EVM: Fix Environmental location

The am3517-evm boards stores the environment in NAND, but after merging
various configs, the board was trying to load environment variables from
FAT which would ultimately fail and cause some chatter.

This patch removes the ENV_IS_IN_FAT flag to eliminate the noise.

Signed-off-by: Adam Ford <aford173@gmail.com>

configs/am3517_evm_defconfig

@@ -30,6 +30,7 @@ CONFIG_MTDIDS_DEFAULT="nand0=omap2-nand.0"
 CONFIG_MTDPARTS_DEFAULT="mtdparts=omap2-nand.0:512k(MLO),1920k(u-boot),256k(u-boot-env),8m(kernel),512k(dtb),-(rootfs)"
 CONFIG_CMD_UBI=y
 CONFIG_OF_CONTROL=y
+# CONFIG_ENV_IS_IN_FAT is not set
 CONFIG_ENV_IS_IN_NAND=y
 CONFIG_MMC_OMAP_HS=y
 CONFIG_NAND=y