drivers: net: Soft reset felix switch core

It turns out that in custom designs if the system is reset
multiple times in conjunction with a slight increase in external
temperature, the felix  switch starts to behave in a strange way:
packets are no longer received on the ENECT interface connected
to the L2switch internal port (the TX side of internal port stops working
or the packets do not reach there. It is not very clear where
the packets remain blocked. None of the counters points to a disruption
in the L2switch)
The issue is not reproducible on NXP reference designs.

It was observed that by adding the switch core reset, the problem
goes aways, even if intensive testing in temperature chambers
is applied.

The current patch performs soft reset on the switch core to ensure proper
operation of the L2switch.

Signed-off-by: Radu Bulie <radu-andrei.bulie@nxp.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>