mb862xxfb: update Valentin's email address

Since Valentin's email address @siemens.com is no longer valid, it's time
to change it to the one that actually works so that I don't have to
manually forward patches against mb862xx to him every time.

Signed-off-by: Alexander Shishkin <virtuoso@slind.org>
Acked-by: Valentin Sitdikov <v.sitdikov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>