of: thermal: Improve print information

Define pr_fmt macro to add a prefix to the message, this can make the thermal log better recognized.

Before:

[    0.602672] nfc: nfc_init: NFC Core ver 0.1
[    0.602828] NET: Registered protocol family 39
[    0.603435] clocksource: Switched to clocksource mct-frc
[    0.746216] failed to build thermal zone cpu-thermal: -22
[    0.746451] NET: Registered protocol family 2

After:

[    0.602804] NET: Registered protocol family 39
[    0.603463] clocksource: Switched to clocksource mct-frc
[    0.746309] thermal_sys: failed to build thermal zone cpu-thermal: -22
[    0.746545] NET: Registered protocol family 2

---
 drivers/thermal/of-thermal.c | 3 +++
 1 file changed, 3 insertions(+)

index 4bfdb4a1e47d..02b5e78f027b 100644
@@ -5,6 +5,9 @@
  *  Copyright (C) 2013 Texas Instruments
  *  Copyright (C) 2013 Eduardo Valentin <[email protected]>
  */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <linux/thermal.h>
 #include <linux/slab.h>
 #include <linux/types.h>

2.17.0