Convert CONFIG_FLASH_SHOW_PROGRESS to Kconfig

This converts the following to Kconfig:
   CONFIG_FLASH_SHOW_PROGRESS

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/M5235EVB_defconfig b/configs/M5235EVB_defconfig
index b099e98..cb5bcb7 100644
--- a/configs/M5235EVB_defconfig
+++ b/configs/M5235EVB_defconfig
@@ -44,6 +44,7 @@
 CONFIG_MTD_NOR_FLASH=y
 CONFIG_FLASH_CFI_DRIVER=y
 CONFIG_SYS_FLASH_CFI_WIDTH_16BIT=y
+CONFIG_FLASH_SHOW_PROGRESS=0
 CONFIG_SYS_FLASH_PROTECTION=y
 CONFIG_SYS_FLASH_CFI=y
 CONFIG_SYS_MAX_FLASH_SECT=137