drm: Simplify drm_printk to reduce object size quite a bit

Remove function name and special " *ERROR*" from argument list

$ size drivers/gpu/drm/built-in.o* (x86-32 defconfig, most drm selected)
   text	   data	    bss	    dec	    hex	filename
5635366	 182579	  14328	5832273	 58fe51	drivers/gpu/drm/built-in.o.new
5779552	 182579	  14328	5976459	 5b318b	drivers/gpu/drm/built-in.o.old

Using "%ps", __builtin_return_address(0) is the same as "%s", __func__
except for static inlines, but it's more or less the same output.

Miscellanea:

o Convert args... to ##__VA_ARGS__
o The equivalent DRM_DEV_<FOO> macros are rarely used and not
  worth conversion

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/01f976d5ab93c985756fc1b2e83656fb0a2a28c8.1474856262.git.joe@perches.com