ACPI: FFH: Drop the inclusion of linux/arm-smccc.h

The inclusion of linux/arm-smccc.h in acpi_ffh is unnecessary and can
be even termed wrong. It is needed in the arm64 architecture callback
implementation and probably is the leftover from the missed cleanup of
the initial implementation.

Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI: Implement a generic FFH Opregion handler

This registers the FFH OpRegion handler before ACPI tables are
loaded. The platform support for the same is checked via Platform-Wide
OSPM Capabilities(OSC) before registering the OpRegion handler.

It relies on the special context data passed to offset and the length.
However the interpretation of the values is platform/architecture
specific. This generic handler just passed all the information to
the platform/architecture specific callback. It also implements the
default callbacks which return as not supported.

Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>