hw/mcu/dialog: Acquire PD_SYS for DMA
hw/mcu/dialog: Acquire PD_SYS for DMA

DMA controller resides in PD_SYS domain so we cannot turn off that
domain if any DMA channes is acquired. That basically means on 1st
acquired DMA channel we need to also acquire PD which we can release
after last DMA channel is released. Note that acquiring PD_SYS means
M33 cannot be powered down in deep sleep.

mlaz/mynewt-core,mlaz/mynewt-core,mlaz/mynewt-core,mlaz/mynewt-core,mlaz/mynewt-core