net: enetc: add multiple command BD rings support

net: enetc: add multiple command BD rings support

All the tables of NETC switch are managed through the command BD ring,
but unlike ENETC, the switch has two command BD rings, if the current
ring is busy, the switch driver can switch to another ring to manage
the table. Currently, the NTMP driver does not support multiple rings.
Therefore, update ntmp_select_and_lock_cbdr() to select a appropriate
ring to execute the command for the switch.

Signed-off-by: Wei Fang <wei.fang@nxp.com>
Link: https://patch.msgid.link/20260518082506.1318236-9-wei.fang@nxp.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>