ACPI: disable _OSI(Windows 2009) on Asus K50IJ

Fix a win7 compability issue on Asus K50IJ.

Here is the _BCM method of this laptop:
                    Method (_BCM, 1, NotSerialized)
                    {
                        If (LGreaterEqual (OSFG, OSVT))
                        {
                            If (LNotEqual (OSFG, OSW7))
                            {
                                Store (One, BCMD)
                                Store (GCBL (Arg0), Local0)
                                Subtract (0x0F, Local0, LBTN)
                                ^^^SBRG.EC0.STBR ()
                                ...
                            }
                            Else
                            {
                                DBGR (0x0B, Zero, Zero, Arg0)
                                Store (Arg0, LBTN)
                                ^^^SBRG.EC0.STBR ()
                                ...
                            }
                        }
                    }
LBTN is used t...