drm/i915: Convert pipe_config_buffer_mismatch() to drm_printer

Utilize drm_printer in pipe_config_infoframe_mismatch() to avoid
a bit of code duplication.

print_hex_dump() doesn't know anything about the printer so
it still needs the DRM_UT_KMS check and special handling for
the loglevel. But at least we end up with a bit less copy-pasta.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240215164055.30585-6-ville.syrjala@linux.intel.comReviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drivers/gpu/drm/i915/display/intel_display.c

@@ -4876,33 +4876,34 @@ pipe_config_buffer_mismatch(bool fastset, const struct intel_crtc *crtc,
 			    const char *name,
 			    const u8 *a, const u8 *b, size_t len)
 {
-	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
+	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
+	struct drm_printer p;
+	const char *loglevel;
 
 	if (fastset) {
 		if (!drm_debug_enabled(DRM_UT_KMS))
 			return;
 
-		/* only dump up to the last difference */
-		len = memcmp_diff_len(a, b, len);
+		p = drm_dbg_printer(&i915->drm, DRM_UT_KMS, NULL);
+		loglevel = KERN_DEBUG;
 
-		drm_dbg_kms(&dev_priv->drm,
-			    "[CRTC:%d:%s] fastset requirement not met in %s buffer\n",
+		drm_printf(&p, "[CRTC:%d:%s] fastset requirement not met in %s buffer\n",
 			   crtc->base.base.id, crtc->base.name, name);
-		print_hex_dump(KERN_DEBUG, "expected: ", DUMP_PREFIX_NONE,
-			       16, 0, a, len, false);
-		print_hex_dump(KERN_DEBUG, "found: ", DUMP_PREFIX_NONE,
-			       16, 0, b, len, false);
 	} else {
+		p = drm_err_printer(&i915->drm, NULL);
+		loglevel = KERN_ERR;
+
+		drm_printf(&p, "[CRTC:%d:%s] mismatch in %s buffer\n",
+			   crtc->base.base.id, crtc->base.name, name);
+	}
+
 	/* only dump up to the last difference */
 	len = memcmp_diff_len(a, b, len);
 
-		drm_err(&dev_priv->drm, "[CRTC:%d:%s] mismatch in %s buffer\n",
-			crtc->base.base.id, crtc->base.name, name);
-		print_hex_dump(KERN_ERR, "expected: ", DUMP_PREFIX_NONE,
+	print_hex_dump(loglevel, "expected: ", DUMP_PREFIX_NONE,
 		       16, 0, a, len, false);
-		print_hex_dump(KERN_ERR, "found: ", DUMP_PREFIX_NONE,
+	print_hex_dump(loglevel, "found: ", DUMP_PREFIX_NONE,
 		       16, 0, b, len, false);
-	}
 }
 
 static void __printf(4, 5)