samsung_pwm: fix build for CONFIG_CLKSRC_SAMSUNG_PWM=n

From: Bartlomiej Zolnierkiewicz <[email protected]>
Subject: [linux-next PATCH] samsung_pwm: fix build for CONFIG_CLKSRC_SAMSUNG_PWM=n

If CONFIG_PWM_SAMSUNG=y and CONFIG_CLKSRC_SAMSUNG_PWM=n next-20130626 build fails with the following error:

drivers/pwm/pwm-samsung.c:89:19: error: static declaration of ?samsung_pwm_lock? follows non-static declaration include/clocksource/samsung_pwm.h:23:19: note: previous declaration of ?samsung_pwm_lock? was here

It is caused by commit 9ebe293 ("pwm: Add new pwm-samsung driver").

Fix it by adding missing ifdef.

---
 include/clocksource/samsung_pwm.h |    2 ++
 1 file changed, 2 insertions(+)

Index: b/include/clocksource/samsung_pwm.h
===================================================================
@@ -20,7 +20,9 @@
 
 #define SAMSUNG_PWM_NUM		5
 
+#ifdef CONFIG_CLKSRC_SAMSUNG_PWM
 extern spinlock_t samsung_pwm_lock;
+#endif
 
 struct samsung_pwm_variant {
 	u8 bits;