dmaengine: jz4780: Fix an endian bug in IRQ handler

The "pending" variable was a u32 but we cast it to an unsigned long
pointer when we do the for_each_set_bit() loop.  The problem is that on
big endian 64bit systems that results in an out of bounds read.

Fixes: 4e4106f5 ("dmaengine: jz4780: Fix transfers being ACKed too soon")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>