armvirt: 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/armvirt/config-4.19

@@ -29,6 +29,7 @@ CONFIG_ARM_GIC_V3=y
 CONFIG_ARM_PSCI_FW=y
 # CONFIG_ARM_SP805_WATCHDOG is not set
 CONFIG_BALLOON_COMPACTION=y
+CONFIG_BLK_DEV_LOOP=y
 CONFIG_BLK_MQ_PCI=y
 CONFIG_BLK_MQ_VIRTIO=y
 CONFIG_BLK_SCSI_REQUEST=y
@@ -42,6 +43,7 @@ CONFIG_CPU_RMAP=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
@@ -55,6 +57,11 @@ CONFIG_DEBUG_BUGVERBOSE=y
 CONFIG_DTC=y
 CONFIG_EDAC_SUPPORT=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_FAILOVER=y
 CONFIG_FIX_EARLYCON_MEM=y
 CONFIG_FRAME_POINTER=y