mailmap: update email address for Muhammad Usama Anjum

mailmap: update email address for Muhammad Usama Anjum

Add updated email address.

Link: https://lkml.kernel.org/r/20260310171757.3970390-1-usama.anjum@arm.com
Signed-off-by: Muhammad Usama Anjum <usama.anjum@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Carlos Bilbao <carlos.bilbao@kernel.org>
Cc: Hans Verkuil <hverkuil@kernel.org>
Cc: Jakub Kacinski <kuba@kernel.org>
Cc: Martin Kepplinger <martink@posteo.de>
Cc: Shannon Nelson <sln@onemain.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>