at91/sama7: Use ext4 driver for ext2 and ext3

Use the ext4 driver for ext2 and ext3 too. This feature is activated in
the OpenWrt generic configuration.

Tested-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

target/linux/at91/sama7/config-default

@@ -147,12 +147,6 @@ CONFIG_EDAC_ATOMIC_SCRUB=y
 CONFIG_EDAC_SUPPORT=y
 CONFIG_EEPROM_AT24=y
 # CONFIG_EFI_PARTITION is not set
-CONFIG_EXT2_FS=y
-# CONFIG_EXT2_FS_POSIX_ACL is not set
-# CONFIG_EXT2_FS_SECURITY is not set
-CONFIG_EXT3_FS=y
-# CONFIG_EXT3_FS_POSIX_ACL is not set
-# CONFIG_EXT3_FS_SECURITY is not set
 CONFIG_EXT4_FS=y
 CONFIG_FANOTIFY=y
 CONFIG_FAT_FS=y