am335x_evm: Convert NOR_BOOT to Kconfig

Signed-off-by: Tom Rini <trini@ti.com>

board/ti/am335x/Kconfig

@@ -29,4 +29,12 @@ config NOR
 	  In practice this is seen as a NOR flash module connected to the
 	  "memory cape" for the BeagleBone family.
 
+config NOR_BOOT
+	bool "Support for booting from NOR flash"
+	depends on NOR
+	help
+	  Enabling this will make a U-Boot binary that is capable of being
+	  booted via NOR.  In this case we will enable certain pinmux early
+	  as the ROM only partially sets up pinmux.  We also default to using
+	  NOR for environment.
 endif

configs/am335x_evm_norboot_defconfig

@@ -1,5 +1,5 @@
-CONFIG_SYS_EXTRA_OPTIONS="NOR_BOOT"
 CONFIG_CONS_INDEX=1
 CONFIG_ARM=y
 CONFIG_TARGET_AM335X_EVM=y
 CONFIG_NOR=y
+CONFIG_NOR_BOOT=y