The vchan lock in edma_callback is acquired in hard interrupt context. As
interrupts are already disabled, there's no point in save/restoring interrupt
mask bit or cpsr flags.

Get rid of flags local variable and use spin_lock instead of spin_lock_irqsave.
Signed-off-by: NJoel Fernandes <joelf@ti.com>
Signed-off-by: NVinod Koul <vinod.koul@intel.com>