ACPI: extend "acpi_osi=" boot option

The boot option "acpi_osi=" has always disabled Linux _OSI support,
thus disabling all OS Interface strings which are advertised
by Linux to the BIOS.

Now...
acpi_osi="string" adds the interface string, and
acpi_osi="!string" invalidates the pre-defined interface string

eg. acpi_osi="!Windows 2006"
would disable Linux's claim of Vista compatibility.

Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/include/acpi/acpiosxf.h b/include/acpi/acpiosxf.h
index 5e07db0..de26ee1 100644
--- a/include/acpi/acpiosxf.h
+++ b/include/acpi/acpiosxf.h
@@ -236,6 +236,7 @@
  * Miscellaneous
  */
 acpi_status acpi_os_validate_interface(char *interface);
+acpi_status acpi_osi_invalidate(char* interface);
 
 acpi_status
 acpi_os_validate_address(u8 space_id,