TWL4030: remove superfluous PWR interrupt status clear before masking

twl_irq_init() clears PWR interrupt status bits, then masks the interrupts
off, then clears the PWR interrupt status bits again.  The first clear
seems unnecessary, so, remove it.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>