Convert CONFIG_SYS_MAX_FLASH_SECT to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_MAX_FLASH_SECT

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/integratorap_cm720t_defconfig b/configs/integratorap_cm720t_defconfig
index 71f6450..644876e 100644
--- a/configs/integratorap_cm720t_defconfig
+++ b/configs/integratorap_cm720t_defconfig
@@ -33,5 +33,6 @@
 CONFIG_SYS_FLASH_EMPTY_INFO=y
 CONFIG_SYS_FLASH_PROTECTION=y
 CONFIG_SYS_FLASH_CFI=y
+CONFIG_SYS_MAX_FLASH_SECT=128
 CONFIG_BAUDRATE=38400
 CONFIG_OF_LIBFDT=y