drivers: gpdma: power flow refactor

This patch is refactoring device power flow routine. DMA instance will
not be power up after kernel initialization if device power management
is enabled. Power menager will power up device and its power domain if
device will be in use and disable it when it's no longer needed.

The DMA disabling part has not yet been implemented.

Signed-off-by: Tomasz Leman <tomasz.m.leman@intel.com>