net: natsemi: Replace in_interrupt() usage.

The usage of in_interrupt() in drivers is phased out and Linus clearly
requested that code which changes behaviour depending on context should
either be seperated or the context be conveyed in an argument passed by the
caller, which usually knows the context.

sonic_quiesce() uses 'in_interrupt() || irqs_disabled()' to chose either
udelay() or usleep_range() in the wait loop.

In all callchains leading to it the context is well defined and known.

Add a 'may_sleep' argument and pass it through the various callchains
leading to this function.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>