ACPI / boot: Correct address space of __acpi_map_table()

Sparse complains about wrong address space used in __acpi_map_table()
and in __acpi_unmap_table().

arch/x86/kernel/acpi/boot.c:127:29: warning: incorrect type in return expression (different address spaces)
arch/x86/kernel/acpi/boot.c:127:29:    expected char *
arch/x86/kernel/acpi/boot.c:127:29:    got void [noderef] <asn:2>*
arch/x86/kernel/acpi/boot.c:135:23: warning: incorrect type in argument 1 (different address spaces)
arch/x86/kernel/acpi/boot.c:135:23:    expected void [noderef] <asn:2>*addr
arch/x86/kernel/acpi/boot.c:135:23:    got char *map

Correct address space to be in align of type of returned and passed
parameter.

Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>