drm/i915/skl: Remove unnecessary () used with abs_diff()

abs_diff() properly protects its parameters, so no need for the outer ()
here.
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_ddi.c

@@ -1239,7 +1239,7 @@ skl_ddi_calculate_wrpll(int clock /* in Hz */,
 		if (found) {
 			dco_central_freq_deviation[dco_count] =
 				div64_u64(10000 *
-					  abs_diff((candidate_p * afe_clock),
+					  abs_diff(candidate_p * afe_clock,
 						   dco_central_freq[dco_count]),
 					  dco_central_freq[dco_count]);