Properly alphabetize MAINTAINERS file

This adds a perl script to actually parse the MAINTAINERS file, clean up
some whitespace in it, warn about errors in it, and then properly sort
the end result.

My perl-fu is atrocious, so the script has basically been created by
randomly putting various characters in a pile, mixing them around, and
then looking it the end result does anything interesting when used as a
perl script.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>