drm/i915: convert force_wake_get to func pointer in the gpu reset code

drm/i915: convert force_wake_get to func pointer in the gpu reset code

commit 8109021313c7a3d8947677391ce6ab9cd0bb1d28 upstream.

This was forgotten in the original multi-threaded forcewake
conversion:

commit 8d715f0024f64ad1b1be85d8c081cf577944c847
Author: Keith Packard <keithp at keithp.com>
Date:   Fri Nov 18 20:39:01 2011 -0800

    drm/i915: add multi-threaded forcewake support

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Eugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Eugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>