MN10300: Fix endianess of ext2 bitops

The MN10300 arch ext2 bitops assume a big-endian kernel, but the MN10300
arch only runs in little-endian mode.

Reported-by: Akira Takeuchi <takeuchi.akr@jp.panasonic.com>
Signed-off-by: Mark Salter <msalter@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>