net: dsa: bcm_sf2: Call setup during switch resume

[ Upstream commit 54baca096386d862d19c10f58f34bf787c6b3cbe ]

There is no reason to open code what the switch setup function does, in
fact, because we just issued a switch reset, we would make all the
register get their default values, including for instance, having unused
port be enabled again and wasting power and leading to an inappropriate
switch core clock being selected.

Fixes: 8cfa9498 ("net: dsa: bcm_sf2: add suspend/resume callbacks")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>