staging/nvec: update comment regarding udelay in the isr

Update the comment before the udelay on how to replace it.

Signed-off-by: Marc Dietrich <marvin24@gmx.de>
Link: https://lore.kernel.org/r/20240218212557.22836-1-marvin24@gmx.de


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>