drm/i915: Replace *_reference/unreference() or *_ref/unref with _get/put()

Replace instances of drm_framebuffer_reference/unreference() with
*_get/put() suffixes and drm_dev_unref with *_put() suffix
because get/put is shorter and consistent with the
kernel use of *_get/put suffixes.
Done with following coccinelle semantic patch

@@
expression ex;
@@

(
-drm_framebuffer_unreference(ex);
+drm_framebuffer_put(ex);
|
-drm_dev_unref(ex);
+drm_dev_put(ex);
|
-drm_framebuffer_reference(ex);
+drm_framebuffer_get(ex);
)

Signed-off-by: Harsha Sharma <harshasharmaiitr@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20171014183644.21990-1-harshasharmaiitr@gmail.com