Convert the per stream queue spinlocks into mutexes.  All queue
manipulation happens via the work queue or system calls into the driver, and
not in an interrupt context.  This reduces the amout of time the cx18 driver
keeps interrupts disabled.
Signed-off-by: NAndy Walls <awalls@radix.net>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>