[ARM] pxa: add parameter to clksrc_read() for pxa168/910

This patch modifies parameter of clksrc_read() from 'void' to
'struct clocksource *cs', which fixes compile warning for
incompatible parameter type.
Signed-off-by: NColy Li <coly.li@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NEric Miao <eric.miao@marvell.com>

arch/arm/mach-mmp/time.c

@@ -136,7 +136,7 @@ static struct clock_event_device ckevt = {
 	.set_mode	= timer_set_mode,
 };
 
-static cycle_t clksrc_read(void)
+static cycle_t clksrc_read(struct clocksource *cs)
 {
 	return timer_read();
 }