ACPI: fix acpi_osi=!Linux

Need to check for special case "acpi_osi=!Linux" before handling the
general case "acpi_osi=!*", or it will have no effect.

Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>