[media] it913x ver 1.26 change to remove interruptible mutex locks

Some virtual I2C commands are missed along some PID filtering
commands resulting complete stall of driver.

Since dvb-usb cannot handle the -EAGAIN error and commands
generally should not be missed mutex_lock is used instead.

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>