enic: enic rq code reorg

enic: enic rq code reorg

Separates enic rx path from generic vnic api. Removes some
complexity of doign enic callbacks through vnic api in rx.
This is in preparation for enabling enic extended cq which
applies only to enic rx path.

Co-developed-by: Nelson Escobar <neescoba@cisco.com>
Signed-off-by: Nelson Escobar <neescoba@cisco.com>
Co-developed-by: John Daley <johndale@cisco.com>
Signed-off-by: John Daley <johndale@cisco.com>
Signed-off-by: Satish Kharat <satishkh@cisco.com>
Link: https://patch.msgid.link/20250304-enic_cleanup_and_ext_cq-v2-2-85804263dad8@cisco.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>