rcar-hpbdma: remove shdma_free_irq() calls

rcar-hpbdma: remove shdma_free_irq() calls

Commit 3d88b6d1a994e5d3664473067d5674ea42370060 (DMA: shdma: switch to managed
resource allocation) got rid of shdma_free_irq() but  unfortunately got merged
later than commit 95f89066cdaef75e03a28748abd0a8be926b7137 (dma: add driver for
R-Car HPB-DMAC), so that the HPB-DMAC driver retained the calls and got broken:

drivers/dma/sh/rcar-hpbdma.c: In function `hpb_dmae_alloc_chan_resources':
drivers/dma/sh/rcar-hpbdma.c:435: error: implicit declaration of function
`shdma_free_irq'

Fix this compilation error by removing the remaining shdma_free_irq() calls.

Reported-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Tested-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>