clocksource: pxa: Fix section mismatch

As pxa_timer_common_init() is only called in init context, mark it as
such, and quiesce the compiler warnings :
WARNING: vmlinux.o(.text.unlikely+0x45d4): Section mismatch in reference
from the function pxa_timer_common_init() to the function
.init.text:sched_clock_register()

WARNING: vmlinux.o(.text.unlikely+0x4610): Section mismatch in reference
from the function pxa_timer_common_init() to the function
.init.text:clocksource_mmio_init()
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

drivers/clocksource/pxa_timer.c

@@ -163,7 +163,7 @@ static struct irqaction pxa_ost0_irq = {
 	.dev_id		= &ckevt_pxa_osmr0,
 };
 
-static void pxa_timer_common_init(int irq, unsigned long clock_tick_rate)
+static void __init pxa_timer_common_init(int irq, unsigned long clock_tick_rate)
 {
 	timer_writel(0, OIER);
 	timer_writel(OSSR_M0 | OSSR_M1 | OSSR_M2 | OSSR_M3, OSSR);