Merge branch 'dsa-mv88e6xxx-ATU-VTU-irq-fixes'

Andrew Lunn says:

====================
ATU and VTU irq fixes

Further testing and code review found two sets of bugs.

Core review found a cut/paste error in the irq setup code.

A board which does not have an interrupt line from the switch to the
SoC, and experiancing an EPROBE_DEFER throw a splat when the ATU irq
was freed but never registered.

v2: Fix typ0 chip->chip->vtu_prob_irq to chip->vtu_prob_irq
    0-day compile testing.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>