drm/i915: Remove function details from device error messages

Error messages are intended to be addressed to the user; be clear,
succinct, instructive and unambiguous. Adding the function name to
that message does not add any information the user requires and in
the process makes the message less clear.

E.g.

[  245.539711] i915 0000:00:02.0: [drm:i915_gem_init [i915]] Failed to initialize GPU, declaring it wedged!

becomes

[  245.539711] i915 0000:00:02.0: Failed to initialize GPU, declaring it wedged!
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180709134858.12446-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_drv.c

@@ -104,8 +104,13 @@ __i915_printk(struct drm_i915_private *dev_priv, const char *level,
 	vaf.fmt = fmt;
 	vaf.va = &args;
 
-	dev_printk(level, kdev, "[" DRM_NAME ":%ps] %pV",
-		   __builtin_return_address(0), &vaf);
+	if (is_error)
+		dev_printk(level, kdev, "%pV", &vaf);
+	else
+		dev_printk(level, kdev, "[" DRM_NAME ":%ps] %pV",
+			   __builtin_return_address(0), &vaf);
+
+	va_end(args);
 
 	if (is_error && !shown_bug_once) {
 		/*
@@ -117,8 +122,6 @@ __i915_printk(struct drm_i915_private *dev_priv, const char *level,
 			dev_notice(kdev, "%s", FDO_BUG_MSG);
 		shown_bug_once = true;
 	}
-
-	va_end(args);
 }
 
 /* Map PCH device id to PCH type, or PCH_NONE if unknown. */