dmaengine: owl-dma: Fix a resource leak in the remove function

A 'dma_pool_destroy()' call is missing in the remove function.
Add it.

This call is already made in the error handling path of the probe function.

Fixes: 47e20577 ("dmaengine: Add Actions Semi Owl family S900 DMA driver")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/20201212162535.95727-1-christophe.jaillet@wanadoo.fr


Signed-off-by: Vinod Koul <vkoul@kernel.org>