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/integratorcp_cm920t_defconfig b/configs/integratorcp_cm920t_defconfig
index eb9d1b7..61191e2 100644
--- a/configs/integratorcp_cm920t_defconfig
+++ b/configs/integratorcp_cm920t_defconfig
@@ -36,5 +36,6 @@
 CONFIG_SYS_FLASH_EMPTY_INFO=y
 CONFIG_SYS_FLASH_PROTECTION=y
 CONFIG_SYS_FLASH_CFI=y
+CONFIG_SYS_MAX_FLASH_SECT=64
 CONFIG_BAUDRATE=38400
 CONFIG_OF_LIBFDT=y