drm/i915: Rename intel_guc.h to intel_uc.h

GuC is not the only one micro controller we have.

There are also HuC and DMC.

Making the file more general will help with code organization.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michal Winiarski <michal.winiarski@intel.com>
Signed-off-by: Arkadiusz Hiler <arkadiusz.hiler@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1480096777-12573-2-git-send-email-arkadiusz.hiler@intel.com