9p: remove Ron Minnich from MAINTAINERS

9p: remove Ron Minnich from MAINTAINERS

Ron Minnich has left Sandia in 2011, and has not been involved in any 9p
commit in recent years.  Also add a CREDITS entry to record his
contributions.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Dominique Martinet <[email protected]>
Cc: Eric Van Hensbergen <[email protected]>
Cc: Ron Minnich <[email protected]>
Cc: Ronald G. Minnich <[email protected]>
Cc: Latchesar Ionkov <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>