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/sama5d4_xplained_nandflash_defconfig b/configs/sama5d4_xplained_nandflash_defconfig
index e642409..94a2e8e 100644
--- a/configs/sama5d4_xplained_nandflash_defconfig
+++ b/configs/sama5d4_xplained_nandflash_defconfig
@@ -66,6 +66,9 @@
 CONFIG_NAND_ATMEL=y
 CONFIG_PMECC_CAP=8
 CONFIG_SPL_GENERATE_ATMEL_PMECC_HEADER=y
+CONFIG_SYS_NAND_BLOCK_SIZE=0x40000
+CONFIG_SYS_NAND_PAGE_SIZE=0x1000
+CONFIG_SYS_NAND_OOBSIZE=0xe0
 CONFIG_DM_SPI_FLASH=y
 CONFIG_SF_DEFAULT_SPEED=30000000
 CONFIG_SPI_FLASH_ATMEL=y