drm: Create and use drm_err

Reduce drm text size ~1% by using drm_err and
printf extension %pV to emit error messages.

Remove unused macro DRM_MEM_ERROR.

$ size drivers/gpu/drm/built-in.o*
   text	   data	    bss	    dec	    hex	filename
 361159	   9663	    256	 371078	  5a986	drivers/gpu/drm/built-in.o.new
 365416	   9663	    256	 375335	  5ba27	drivers/gpu/drm/built-in.o.old

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/drm_stub.c b/drivers/gpu/drm/drm_stub.c
index 001273d..6d7b083 100644
--- a/drivers/gpu/drm/drm_stub.c
+++ b/drivers/gpu/drm/drm_stub.c
@@ -62,6 +62,26 @@
 struct class *drm_class;
 struct proc_dir_entry *drm_proc_root;
 struct dentry *drm_debugfs_root;
+
+int drm_err(const char *func, const char *format, ...)
+{
+	struct va_format vaf;
+	va_list args;
+	int r;
+
+	va_start(args, format);
+
+	vaf.fmt = format;
+	vaf.va = &args;
+
+	r = printk(KERN_ERR "[" DRM_NAME ":%s] *ERROR* %pV", func, &vaf);
+
+	va_end(args);
+
+	return r;
+}
+EXPORT_SYMBOL(drm_err);
+
 void drm_ut_debug_printk(unsigned int request_level,
 			 const char *prefix,
 			 const char *function_name,
@@ -78,6 +98,7 @@
 	}
 }
 EXPORT_SYMBOL(drm_ut_debug_printk);
+
 static int drm_minor_get_id(struct drm_device *dev, int type)
 {
 	int new_id;