nrf52/qspi: Set the XIPOFFSET according to Nordic datasheet
nrf52/qspi: Set the XIPOFFSET according to Nordic datasheet

For now it is used for debugging purposes however later it can be used
to optimize read from flash

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