drm/i915: Tune down sink crc timeout dmesg output

For whatever reasons this can happen. For real testcases the test will
notice the -EIO and fall over, but we also have some testcases that
just read all debugfs files. And that shouldn't cause dmesg spam.

So tune it down a bit so that we still have the information for
debugging. And change the errno so that real testcases can easily
differentiate.

Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=84890
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

drivers/gpu/drm/i915/intel_dp.c

@@ -3693,8 +3693,8 @@ int intel_dp_sink_crc(struct intel_dp *intel_dp, u8 *crc)
 	} while (--attempts && (buf & DP_TEST_COUNT_MASK) == test_crc_count);
 
 	if (attempts == 0) {
-		DRM_ERROR("Panel is unable to calculate CRC after 6 vblanks\n");
-		return -EIO;
+		DRM_DEBUG_KMS("Panel is unable to calculate CRC after 6 vblanks\n");
+		return -ETIMEDOUT;
 	}
 
 	if (drm_dp_dpcd_read(&intel_dp->aux, DP_TEST_CRC_R_CR, crc, 6) < 0)