DMA: shdma: fix a bad merge - remove free_irq()

A bad merge resulted in a left-over free_irq() call. This patch removes it.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas@gmail.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>