pwm: vt8500: Fix coding style issue

Fixes the following:
WARNING: Prefer pr_warn(... to pr_warning(...
	pr_warning("Waiting for status bits 0x%x to clear timed out\n",
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

drivers/pwm/pwm-vt8500.c

@@ -41,7 +41,7 @@ static inline void pwm_busy_wait(void __iomem *reg, u8 bitmask)
 		cpu_relax();
 
 	if (unlikely(!loops))
-		pr_warning("Waiting for status bits 0x%x to clear timed out\n",
+		pr_warn("Waiting for status bits 0x%x to clear timed out\n",
 			   bitmask);
 }