malta: configure kernel for f2fs and ext4 based overlays

jffs2/mtdblock overlays are long time gone, and as we switch to the new
f2fs/ext4 based overlays, we need to add missing support for loop block
device and f2fs to kernel.

Signed-off-by: Petr Štetiar <ynezz@true.cz>

target/linux/malta/config-4.19

@@ -20,6 +20,7 @@ CONFIG_BLK_DEV_BSG=y
 CONFIG_BLK_DEV_BSGLIB=y
 # CONFIG_BLK_DEV_DM is not set
 # CONFIG_BLK_DEV_INITRD is not set
+CONFIG_BLK_DEV_LOOP=y
 # CONFIG_BLK_DEV_MD is not set
 CONFIG_BLK_DEV_RAM=y
 CONFIG_BLK_DEV_RAM_COUNT=16
@@ -74,6 +75,7 @@ CONFIG_CPU_SUPPORTS_MSA=y
 CONFIG_CRC16=y
 CONFIG_CRYPTO_AEAD=y
 CONFIG_CRYPTO_AEAD2=y
+CONFIG_CRYPTO_CRC32=y
 CONFIG_CRYPTO_CRC32C=y
 CONFIG_CRYPTO_HASH=y
 CONFIG_CRYPTO_HASH2=y
@@ -94,6 +96,11 @@ CONFIG_DTC=y
 CONFIG_DUMMY_CONSOLE=y
 CONFIG_ENABLE_MUST_CHECK=y
 CONFIG_EXT4_FS=y
+# CONFIG_F2FS_CHECK_FS is not set
+CONFIG_F2FS_FS=y
+# CONFIG_F2FS_FS_SECURITY is not set
+CONFIG_F2FS_FS_XATTR=y
+CONFIG_F2FS_STAT_FS=y
 CONFIG_FS_IOMAP=y
 CONFIG_FS_MBCACHE=y
 CONFIG_FS_POSIX_ACL=y