soc: nordic: Include <nrfx.h> instead of <nrf.h> from <soc.h>

This change is done so that there is no need to additionaly include
<nrfx.h> before <soc/nrfx_coredep.h> (what might be a bit surprising)
and so that <nrfx_config.h> doesn't need to be include separately for
nRF SoCs requiring a special mapping of peripheral accessing symbols.

This commit removes also no longer needed inclusions and updates
the hal_nordic module with required minor correction of nrfx_glue.h.

Signed-off-by: Andrzej Głąbek <andrzej.glabek@nordicsemi.no>