ASoC: twl6040: Modify the IRQ handler

Multiples interrupts can be received. The irq handler is modified
to attend all of them.

Signed-off-by: Margarita Olaya Cabrera <magi.olaya@ti.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>