TWL4030: use correct register addresses for BCI IMR registers

The existing code to mask and clear BCI interrupts in twl_init_irq() is
wrong.  It uses the wrong register offsets, it does not mask all of the
BCI IMR registers, and it does not clear all of the BCI ISR registers.

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