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/ls2080ardb_nand_defconfig b/configs/ls2080ardb_nand_defconfig
index cd2cab4..b9f7353 100644
--- a/configs/ls2080ardb_nand_defconfig
+++ b/configs/ls2080ardb_nand_defconfig
@@ -63,6 +63,7 @@
 CONFIG_FLASH_CFI_DRIVER=y
 CONFIG_SYS_FLASH_USE_BUFFER_WRITE=y
 CONFIG_SYS_FLASH_CFI=y
+CONFIG_SYS_NAND_BLOCK_SIZE=0x80000
 CONFIG_PHYLIB=y
 CONFIG_PHY_AQUANTIA=y
 CONFIG_PHY_CORTINA=y