drm/i915: Shrink pipe config checker

Replace INTEL_ERR_OR_DBG_KMS macro with an intel_err_or_dbg_kms
function to shrink the code and rodata strings.

   text    data     bss     dec     hex filename
1271480   41831    2016 1315327  1411ff i915.ko.0
1265160   41831    2016 1309007  13f94f i915.ko.2

Total of ~6 KiB saving across text and strings.

v2:
 * Annotate the function for printf-style checking.
 * Rename to pipe_config_err. (Chris Wilson)

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1481021420-5783-1-git-send-email-tvrtko.ursulin@linux.intel.com