tps65217: Enable KEY_POWER press on AC loss / PWR_BUT

Adaption of the original patch by Andrew Bradford <andrew.bradford@omni-id.com>
Some minor devm_* changes and DT support.

Signed-off-by: Pantelis Antoniou <panto@antoniou-consulting.com>
dt: bone-common: Add interrupt for PMIC

Add support for the PMIC interrupt, supports power-button presses.

Signed-off-by: Pantelis Antoniou <panto@antoniou-consulting.com>