x86: Convert some debug statements to use logging

Move from using debug() to log_debug() so that we don't have to use the
__func__ parameter and can access other logging features.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/x86/cpu/ivybridge/sdram.c b/arch/x86/cpu/ivybridge/sdram.c
index 1a0ec43..0718aef 100644
--- a/arch/x86/cpu/ivybridge/sdram.c
+++ b/arch/x86/cpu/ivybridge/sdram.c
@@ -9,6 +9,8 @@
  * Copyright (C) 2011 Google Inc.
  */
 
+#define LOG_CATEGORY	UCLASS_RAM
+
 #include <common.h>
 #include <dm.h>
 #include <errno.h>
@@ -213,7 +215,7 @@
 
 	ret = mrc_locate_spd(dev, sizeof(peid->spd_data[0]), &data);
 	if (ret) {
-		debug("%s: Could not locate SPD (ret=%d)\n", __func__, ret);
+		log_debug("Could not locate SPD (err=%d)\n", ret);
 		return ret;
 	}