drm/i915/guc: Move guc_{send,recv}() to intel_uc.c

drm/i915/guc: Move guc_{send,recv}() to intel_uc.c

guc_send(), guc_recv() and related functions were introduced in the
i915_guc_submission.c and their scope was limited only to that file.

Those are not submission specific though.
This patch moves moves them to intel_uc.c with intel_ prefix added.

v2: rename intel_guc_log_* functions and clean up intel_guc_send usages

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>
Link: http://patchwork.freedesktop.org/patch/msgid/1480096777-12573-4-git-send-email-arkadiusz.hiler@intel.com
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>