mfd: palmas: Switch to linear domain in all cases

Swith the palmas to linear domain in all cases so in future DT and non
DT cases will work the same.

With this patch children no longer need IRQ resources as it's easier
for them to use regmap_get_virq. So we can remove the resources
definitions.

Signed-off-by: Graeme Gregory <gg@slimlogic.co.uk>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>