mtd: Add a CONFIG_SPL_MTD_SUPPORT for a more full NAND subsystem in SPL

This mainly converts the am335x_spl_bch driver to the "normal" format
which means a slight change to nand_info within the driver.

Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Tom Rini <trini@ti.com>
diff --git a/include/configs/ti_armv7_common.h b/include/configs/ti_armv7_common.h
index 69d69a5..1127b5b 100644
--- a/include/configs/ti_armv7_common.h
+++ b/include/configs/ti_armv7_common.h
@@ -245,6 +245,7 @@
 #define CONFIG_SPL_NAND_BASE
 #define CONFIG_SPL_NAND_DRIVERS
 #define CONFIG_SPL_NAND_ECC
+#define CONFIG_SPL_MTD_SUPPORT
 #define CONFIG_SYS_NAND_U_BOOT_START	CONFIG_SYS_TEXT_BASE
 #define CONFIG_SYS_NAND_U_BOOT_OFFS	0x80000
 #endif