[WATCHDOG] gef_wdt.c: fsl_get_sys_freq() failure not noticed

fsl_get_sys_freq() may return -1 when 'soc' isn't found, but in
gef_wdt_probe() 'freq' is unsigned, so the test doesn't catch that.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

drivers/watchdog/gef_wdt.c

@@ -269,7 +269,7 @@ static int __devinit gef_wdt_probe(struct of_device *dev,
 	bus_clk = 133; /* in MHz */
 
 	freq = fsl_get_sys_freq();
-	if (freq > 0)
+	if (freq != -1)
 		bus_clk = freq;
 
 	/* Map devices registers into memory */