IB/{cxgb3,cxgb4}: Remove unneeded config dependencies

CHELSIO_T3 already depend on INET
CHELSIO_T4 already depend on (IPV6 || IPV6=n)

Signed-off-by: Yuval Shaia <yuval.shaia@oracle.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>