ALSA: hda: Fix implicit definition of pci_iomap() on SH

Include asm/io.h directly so we've got a definition of pci_iomap(), the
current set of includes do this implicitly on most architectures but not
on SH.

Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>