of: use pr_fmt prefix for all console printing

Clean-up all the DT printk functions to use common pr_fmt prefix.

Some print statements such as kmalloc errors were redundant, so just
drop those.

Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Signed-off-by: Rob Herring <robh@kernel.org>
diff --git a/drivers/of/resolver.c b/drivers/of/resolver.c
index d313d49..7414611 100644
--- a/drivers/of/resolver.c
+++ b/drivers/of/resolver.c
@@ -9,6 +9,8 @@
  * version 2 as published by the Free Software Foundation.
  */
 
+#define pr_fmt(fmt)	"OF: resolver: " fmt
+
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>