Convert CONFIG_SYS_NAND_MAX_OOBFREE et al to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_NAND_MAX_OOBFREE
   CONFIG_SYS_NAND_MAX_ECCPOS

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/CHIP_pro_defconfig b/configs/CHIP_pro_defconfig
index 0e7d5e7..2f55845 100644
--- a/configs/CHIP_pro_defconfig
+++ b/configs/CHIP_pro_defconfig
@@ -25,6 +25,7 @@
 CONFIG_SYS_NAND_ONFI_DETECTION=y
 CONFIG_SYS_NAND_PAGE_SIZE=0x1000
 CONFIG_SYS_NAND_OOBSIZE=0x100
+CONFIG_SYS_NAND_MAX_ECCPOS=1664
 CONFIG_AXP_ALDO3_VOLT=3300
 CONFIG_AXP_ALDO4_VOLT=3300
 CONFIG_CONS_INDEX=2