ACPI: fix build warning

CC      drivers/acpi/executer/exregion.o
drivers/acpi/executer/exregion.c: In function
‘acpi_ex_pci_config_space_handler’:
drivers/acpi/executer/exregion.c:369: attention : passing argument 3 of
‘acpi_os_read_pci_configuration’ from incompatible pointer type

exposed by 10270d48



http://bugzilla.kernel.org/show_bug.cgi?id=9989

Signed-off-by: Ming Lin <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>