mcu/nrf5340: Setup virtual flash on app core
mcu/nrf5340: Setup virtual flash on app core

For combine build of app and net core application side
IPC driver sets up image placement and size so network core
bootloader virtual flash driver can use it to read image.

It uses IPC GPMEM[0..1] registers to pass it to net core.
Those registers were not used for anything else yet.

For now network core IPC clears those registers once net core
application start so app core can proceed.

This wait can be later removed when app will not send several hci
reset commands in a row.

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