drm/tilcdc: replace reference/unreference() with get/put

For maintaining consistency with kernel coding style replace
reference/unreference in ref counting functions with get/put.

The following cocci script was used to generate the tilcdc 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: Aishwarya Pant <aishpant@gmail.com>
Acked-by: Jyri Sarha <jsarha@ti.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/3f2f592f6ea28adfea3fd8b70421b2fab38f0b94.1506413698.git.aishpant@gmail.com