linux/qemu_debug: -EXT2, -EXT3

We have EXT4 which can work with both ext2 and ext3. Besides that I
don't use any ext filesystems currently as root under QEMU is mounted
over 9P.

linux/conf/qemu_debug.conf

@@ -2036,12 +2036,10 @@ CONFIG_NVMEM=y
 #
 CONFIG_DCACHE_WORD_ACCESS=y
 CONFIG_FS_IOMAP=y
-CONFIG_EXT2_FS=y
-# CONFIG_EXT2_FS_XATTR is not set
-CONFIG_EXT3_FS=y
-# CONFIG_EXT3_FS_POSIX_ACL is not set
-# CONFIG_EXT3_FS_SECURITY is not set
+# CONFIG_EXT2_FS is not set
+# CONFIG_EXT3_FS is not set
 CONFIG_EXT4_FS=y
+CONFIG_EXT4_USE_FOR_EXT2=y
 # CONFIG_EXT4_FS_POSIX_ACL is not set
 # CONFIG_EXT4_FS_SECURITY is not set
 # CONFIG_EXT4_ENCRYPTION is not set