ACPI 2.0 / ECDT: Split EC_FLAGS_HANDLERS_INSTALLED

This patch splits EC_FLAGS_HANDLERS_INSTALLED so that address space handler
can be installed when it is not possible to install GPE handler during
early stage.
This patch also tunes address space handler installation, making it
happening earlier than GPE handler installation for the same purpose.

Since acpi_ec_start()/acpi_ec_stop() will be entered multiple times after
applying this change, it is also required to protect acpi_enable_gpe()/
acpi_disable_gpe() invocations.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=112911


Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Tested-by: Chris Bainbridge <chris.bainbridge@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>