axp152: Add axp152 pmu driver

Based on Henrik Nordstrom's axp209 code and Simon "theRat" 's modifications
to the axp209 code for axp152 support.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Henrik Nordstrom <henrik@henriknordstrom.net>