drm/i915: Clean up intel_get_dram_info() a bit

Remove the pointless zero initialization of bunch of things
(the thing is kzalloc()ed).

Also throw out the mostly useless on-stack string. I think
it'll be clear enough from the logs that 0 means unknown.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190306203551.24592-11-ville.syrjala@linux.intel.com

drivers/gpu/drm/i915/i915_drv.c

@@ -1363,14 +1363,8 @@ static void
 intel_get_dram_info(struct drm_i915_private *dev_priv)
 {
 	struct dram_info *dram_info = &dev_priv->dram_info;
-	char bandwidth_str[32];
 	int ret;
 
-	dram_info->valid = false;
-	dram_info->ranks = 0;
-	dram_info->bandwidth_kbps = 0;
-	dram_info->num_channels = 0;
-
 	/*
 	 * Assume 16Gb DIMMs are present until proven otherwise.
 	 * This is only used for the level 0 watermark latency
@@ -1391,12 +1385,10 @@ intel_get_dram_info(struct drm_i915_private *dev_priv)
 	if (ret)
 		return;
 
-	if (dram_info->bandwidth_kbps)
-		sprintf(bandwidth_str, "%d KBps", dram_info->bandwidth_kbps);
-	else
-		sprintf(bandwidth_str, "unknown");
-	DRM_DEBUG_KMS("DRAM bandwidth:%s, total-channels: %u\n",
-		      bandwidth_str, dram_info->num_channels);
+	DRM_DEBUG_KMS("DRAM bandwidth: %u kBps, channels: %u\n",
+		      dram_info->bandwidth_kbps,
+		      dram_info->num_channels);
+
 	DRM_DEBUG_KMS("DRAM ranks: %u, 16Gb DIMMs: %s\n",
 		      dram_info->ranks, yesno(dram_info->is_16gb_dimm));
 }