Convert CONFIG_SPL_NAND_LOAD et al to Kconfig

This converts the following to Kconfig:
   CONFIG_SPL_NAND_LOAD
   CONFIG_SYS_NAND_BLOCK_SIZE
   CONFIG_SYS_NAND_PAGE_SIZE
   CONFIG_SYS_NAND_OOBSIZE

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/am335x_guardian_defconfig b/configs/am335x_guardian_defconfig
index fe8ddf6..19647a9 100644
--- a/configs/am335x_guardian_defconfig
+++ b/configs/am335x_guardian_defconfig
@@ -88,6 +88,9 @@
 CONFIG_MTD=y
 CONFIG_DM_MTD=y
 CONFIG_MTD_RAW_NAND=y
+CONFIG_SYS_NAND_BLOCK_SIZE=0x40000
+CONFIG_SYS_NAND_PAGE_SIZE=0x1000
+CONFIG_SYS_NAND_OOBSIZE=0x100
 CONFIG_SYS_NAND_U_BOOT_LOCATIONS=y
 CONFIG_SYS_NAND_U_BOOT_OFFS=0x100000
 CONFIG_SYS_NAND_U_BOOT_OFFS_REDUND=0x200000