commit 19e353f2 upstream.

The intention is obviously to sign-extend a 12 bit quantity. But
because of C's promotion rules, the assignment is equivalent to "val16
&= 0xfff;". Use the proper API for this.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>