MN10300: Add reads[bwl]() and writes[bwl]()

Add reads[bwl]() and writes[bwl]() for MN10300.

Signed-off-by: Akira Takeuchi <takeuchi.akr@jp.panasonic.com>
Signed-off-by: Kiyoshi Owada <owada.kiyoshi@jp.panasonic.com>
Signed-off-by: David Howells <dhowells@redhat.com>