The simple function that helps to integrate nrfx IRQ handlers with
the IRQ_CONNECT macro can be used in shims for various nrfx drivers,
not only the SPI one.
Similarly, the macro for getting the IRQ number from the peripheral
base address needs to be widely available. It should be even moved
to <nrfx_common.h> in some next nrfx update.
Signed-off-by: Andrzej Głąbek <andrzej.glabek@nordicsemi.no>