dmaengine: coh901318: Fix a double lock bug in dma_tc_handle()

The caller is already holding the lock so this will deadlock.

Fixes: 0b58828c

 ("DMAENGINE: COH 901 318 remove irq counting")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20200217144050.3i4ymbytogod4ijn@kili.mountain
Signed-off-by: Vinod Koul <vkoul@kernel.org>