MAINTAINERS: update email address for Khalid Aziz

Signed-off-by: Khalid Aziz <khalid.aziz@hp.com>
Cc: Khalid Aziz <khalid@gonehiking.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>