drm/i915/dg2: Print PHY name properly on calibration error

We need to use phy_name() to convert the PHY value into a human-readable
character in the error message.

Fixes: a6a12811 ("drm/i915/dg2: Wait for SNPS PHY calibration during display init")
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Swathi Dhanavanthri <swathi.dhanavanthri@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220215163545.2175730-1-matthew.d.roper@intel.com
(cherry picked from commit 84073e56)
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

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

@@ -34,7 +34,7 @@ void intel_snps_phy_wait_for_calibration(struct drm_i915_private *dev_priv)
 		if (intel_de_wait_for_clear(dev_priv, ICL_PHY_MISC(phy),
 					    DG2_PHY_DP_TX_ACK_MASK, 25))
 			DRM_ERROR("SNPS PHY %c failed to calibrate after 25ms.\n",
-				  phy);
+				  phy_name(phy));
 	}
 }