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/taurus_defconfig b/configs/taurus_defconfig
index 0bb28d4..6ae2912 100644
--- a/configs/taurus_defconfig
+++ b/configs/taurus_defconfig
@@ -79,6 +79,9 @@
 CONFIG_MTD_RAW_NAND=y
 # CONFIG_SYS_NAND_USE_FLASH_BBT is not set
 CONFIG_NAND_ATMEL=y
+CONFIG_SYS_NAND_BLOCK_SIZE=0x20000
+CONFIG_SYS_NAND_PAGE_SIZE=0x800
+CONFIG_SYS_NAND_OOBSIZE=0x40
 CONFIG_DM_SPI_FLASH=y
 CONFIG_SPI_FLASH_STMICRO=y
 CONFIG_PHYLIB=y