This fetches the required firmware image from the filesystem,
then loads it into the GuC's memory via a dedicated DMA engine.

This patch is derived from GuC loading work originally done by
Vinit Azad and Ben Widawsky.

v2:
    Various improvements per review comments by Chris Wilson

v3:
    Removed 'wait' parameter to intel_guc_ucode_load() as firmware
        prefetch is no longer supported in the common firmware loader,
	per Daniel Vetter's request.
    Firmware checker callback fn now returns errno rather than bool.

v4:
    Squash uC-independent code into GuC-specifc loader [Daniel Vetter]
    Don't keep the driver working (by falling back to execlist mode)
        if GuC firmware loading fails [Daniel Vetter]

v5:
    Clarify WOPCM-related #defines [Tom O'Rourke]
    Delete obsolete code no longer required with current h/w & f/w
        [Tom O'Rourke]
    Move the call to intel_guc_ucode_init() later, so that it can
        allocate GEM objects, and have it fetch the firmware; then
	intel_guc_ucode_load() doesn't need to fetch it later.
        [Daniel Vetter].

v6:
    Update comment describing intel_guc_ucode_load() [Tom O'Rourke]

Issue: VIZ-4884
Signed-off-by: NAlex Dai <yu.dai@intel.com>
Signed-off-by: NDave Gordon <david.s.gordon@intel.com>
Reviewed-by: NTom O'Rourke <Tom.O'Rourke@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

intel_guc_fwif.h contains the subset of the GuC interface that we
will need for submission of commands through the GuC. These MUST
be kept in sync with the definitions used by the GuC firmware, and
updates to this file will (or should) be autogenerated from the
source files used to build the firmware. Editing this file is
therefore not recommended.

i915_guc_reg.h contains definitions of GuC-related hardware:
registers, bitmasks, etc. These should match the BSpec.

v2:
    Files renamed & resliced per review comments by Chris Wilson

v4:
    Added DON'T-EDIT-ME warning [Tom O'Rourke]

Issue: VIZ-4884
Signed-off-by: NAlex Dai <yu.dai@intel.com>
Signed-off-by: NDave Gordon <david.s.gordon@intel.com>
Reviewed-by: NTom O'Rourke <Tom.O'Rourke@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>