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/T2080QDS_SPIFLASH_defconfig b/configs/T2080QDS_SPIFLASH_defconfig
index fc447ab..2777613 100644
--- a/configs/T2080QDS_SPIFLASH_defconfig
+++ b/configs/T2080QDS_SPIFLASH_defconfig
@@ -110,6 +110,7 @@
 CONFIG_SYS_FLASH_EMPTY_INFO=y
 CONFIG_FLASH_CFI_MTD=y
 CONFIG_SYS_FLASH_CFI=y
+CONFIG_SYS_MAX_FLASH_SECT=1024
 CONFIG_SYS_MAX_FLASH_BANKS=2
 CONFIG_DM_SPI_FLASH=y
 CONFIG_SF_DEFAULT_SPEED=10000000