net: dsa: qca8k: fix internal delay applied to the wrong PAD config

With SGMII phy the internal delay is always applied to the PAD0 config.
This is caused by the falling edge configuration that hardcode the reg
to PAD0 (as the falling edge bits are present only in PAD0 reg)
Move the delay configuration before the reg overwrite to correctly apply
the delay.

Fixes: cef08115 ("net: dsa: qca8k: set internal delay also for sgmii")
Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>