net: dsa: mv88e6xxx: Fix port_hidden_wait to account for port_base_addr

The other port_hidden functions rely on the port_read/port_write
functions to access the hidden control port. These functions apply the
offset for port_base_addr where applicable. Update port_hidden_wait to
use the port_wait_bit so that port_base_addr offsets are accounted for
when waiting for the busy bit to change.

Without the offset the port_hidden_wait function would timeout on
devices that have a non-zero port_base_addr (e.g. MV88E6141), however
devices that have a zero port_base_addr would operate correctly (e.g.
MV88E6390).

Fixes: 60907013 ("net: dsa: mv88e6xxx: update code operating on hidden registers")
Signed-off-by: Nathan Rossi <nathan@nathanrossi.com>
Reviewed-by: Marek Behún <kabel@kernel.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20220425070454.348584-1-nathan@nathanrossi.com


Signed-off-by: Paolo Abeni <pabeni@redhat.com>