powerpc/configs/64s: Use EXT4 to mount EXT2 filesystems

The ext4 code will mount ext2 filesystems, no need to build in both.
Suggested-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230420051609.1324201-1-mpe@ellerman.id.au

arch/powerpc/configs/ppc64_defconfig

@@ -319,10 +319,6 @@ CONFIG_VIRTIO_BALLOON=m
 CONFIG_VHOST_NET=m
 CONFIG_RAS=y
 CONFIG_LIBNVDIMM=y
-CONFIG_EXT2_FS=y
-CONFIG_EXT2_FS_XATTR=y
-CONFIG_EXT2_FS_POSIX_ACL=y
-CONFIG_EXT2_FS_SECURITY=y
 CONFIG_EXT4_FS=y
 CONFIG_EXT4_FS_POSIX_ACL=y
 CONFIG_EXT4_FS_SECURITY=y