[ARM] 4842/1: pxa: remove redundant IRQ saving/restoring in clk_pxa3xx_cken_*

This is unnecessary since it is already protected by
spin_lock_irq{save, restore} in clock.c.

Signed-off-by: eric miao <eric.miao@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>