ARM: pxa: introduce pxa2xx_clock_sysclass for clock suspend/resume

Signed-off-by: Eric Miao <eric.y.miao@gmail.com>
diff --git a/arch/arm/mach-pxa/clock.h b/arch/arm/mach-pxa/clock.h
index 0434878..8ffc1d0 100644
--- a/arch/arm/mach-pxa/clock.h
+++ b/arch/arm/mach-pxa/clock.h
@@ -1,3 +1,4 @@
+#include <linux/sysdev.h>
 #include <asm/clkdev.h>
 
 struct clkops {
@@ -53,6 +54,8 @@
 void clk_pxa2xx_cken_enable(struct clk *clk);
 void clk_pxa2xx_cken_disable(struct clk *clk);
 
+extern struct sysdev_class pxa2xx_clock_sysclass;
+
 #ifdef CONFIG_PXA3xx
 #define DEFINE_PXA3_CKEN(_name, _cken, _rate, _delay)	\
 struct clk clk_##_name = {				\