bnxt_en: wildcard smac while creating tunnel decap filter

While creating a decap filter the tunnel smac need not (and must not) be
specified as we cannot ascertain the neighbor in the recv path. 'ttl'
match is also not needed for the decap filter and must be wild-carded.

Fixes: f484f678 ("bnxt_en: add hwrm FW cmds for cfa_encap_record and decap_filter")
Signed-off-by: Sunil Challa <sunilkumar.challa@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>