MN10300: Tighten up the code using case ranges

Compress a set of consecutive switch cases into a case-range.

Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>