configs: stm32f469-disco: Enable CONFIG_BLK

CONFIG_BLK config flag becomes mandatory, enable it.

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
diff --git a/configs/stm32f469-discovery_defconfig b/configs/stm32f469-discovery_defconfig
index 4de03ed..a55476f 100644
--- a/configs/stm32f469-discovery_defconfig
+++ b/configs/stm32f469-discovery_defconfig
@@ -26,7 +26,6 @@
 CONFIG_CMD_FS_GENERIC=y
 CONFIG_OF_CONTROL=y
 CONFIG_OF_EMBED=y
-# CONFIG_BLK is not set
 CONFIG_DM_MMC=y
 CONFIG_ARM_PL180_MMCI=y
 CONFIG_MTD_NOR_FLASH=y