[media] wl12xx: g_volatile_ctrl fix: wrong field set

The function g_volatile_ctrl should change the current value rather than the
new value. These two drivers didn't do that, so the value is never reported
correctly.

In the future this will change since this behavior is clearly unexpected,
but for now fix these drivers first.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>