ACPI atomicio: Convert width in bits to bytes in __acpi_ioremap_fast()

Callers to __acpi_ioremap_fast() pass the bit_width that they found in the
acpi_generic_address structure. Convert from bits to bytes when passing to
__acpi_find_iomap() - as it wants to see bytes, not bits.

cc: stable@kernel.org
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>