Disable BIOS-enabled GPEs during initialization.

GPEs with corresponding _Lxx/_Exx control methods need to be disabled
during initialization in case they have been enabled by the BIOS, so that
they don't fire up until they are enabled by AcpiUpdateAllGpes().
Rafael J. Wysocki.
Update GPE handler removal, match behavior of handler install.

The OriginallyEnabled check is not paired between AcpiInstallGpeHandler()
and AcpiRemoveGpeHandler(). This patch contains the code that is already in
the Linux kernel upstream. Lv Zheng.