update contact information for Mikael Pettersson

My old @it.uu.se email address is going away, so update relevant
files to point to my @gmail.com address instead.  In sata_promise.c
just delete the address, people can get it from MAINTAINERS.

Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>