In mmp pdma, phy channels are allocated/freed dynamically
and frequently. But no proper protection is added.
Conflict will happen when multi-users are requesting phy
channels at the same time. Use spinlock to protect.
Signed-off-by: NXiang Wang <wangx@marvell.com>
Signed-off-by: NVinod Koul <vinod.koul@intel.com>