ACPI: disable _OSI(Linux) by default

In Linux-2.6.22 we expanded the boot parameter osi=
so that it can enable and !enable an OSI string.

_OSI(Linux) is a special case because we know that there
are both systems that require it set, and systems
require that it _not_ to be set.  In the long term it can't
be set, for the same reason _OS(Linux) can't be enabled --
it tends to confuse BIOS that are not properly
validated with Linux.  Further, the semantics and version
information of _OSI(Linux) were never actually defined.

The kernel prints out a message if it sees _OSI(Linux)
requested, and there is a DMI workaround to invoke
"osi=Linux" automatically for existing systems that need it.

http://bugzilla.kernel.org/show_bug.cgi?id=7787

Signed-off-by: Len Brown <len.brown@intel.com>