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/ls1088aqds_tfa_defconfig b/configs/ls1088aqds_tfa_defconfig
index 8965617..0da726c 100644
--- a/configs/ls1088aqds_tfa_defconfig
+++ b/configs/ls1088aqds_tfa_defconfig
@@ -85,6 +85,7 @@
 CONFIG_SYS_FLASH_USE_BUFFER_WRITE=y
 CONFIG_SYS_FLASH_EMPTY_INFO=y
 CONFIG_SYS_FLASH_CFI=y
+CONFIG_SYS_MAX_FLASH_SECT=1024
 CONFIG_SYS_MAX_FLASH_BANKS=2
 CONFIG_MTD_RAW_NAND=y
 CONFIG_NAND_FSL_IFC=y