net: mvpp2: rework the XLG MAC reset handling

net: mvpp2: rework the XLG MAC reset handling

This patch reworks the way the XLG MAC is set in reset: the XLG MAC is
set in reset at probe time and taken out of this state only when used.
The idea is to move forward a situation where only the blocks used are
taken out of reset. This also has the effect to handle the GMAC and the
XLG MAC in a similar way (the GMAC already is set in reset at boot
time).

Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>