net: wwan: iosm: Replace io.*64_lo_hi() with regular accessors

The io.*_lo_hi() variants are not strictly needed on the x86 hardware
and especially the PCI bus. Replace them with regular accessors, but
leave headers in place in case of 32-bit build.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>