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/ls1043ardb_nand_defconfig b/configs/ls1043ardb_nand_defconfig
index 5b839bc..f4e4d95 100644
--- a/configs/ls1043ardb_nand_defconfig
+++ b/configs/ls1043ardb_nand_defconfig
@@ -69,6 +69,7 @@
 CONFIG_FLASH_CFI_DRIVER=y
 CONFIG_SYS_FLASH_USE_BUFFER_WRITE=y
 CONFIG_SYS_FLASH_CFI=y
+CONFIG_SYS_NAND_BLOCK_SIZE=0x20000
 CONFIG_SF_DEFAULT_BUS=1
 CONFIG_PHYLIB=y
 CONFIG_PHY_AQUANTIA=y