enic: set IG desc cache flag in open

New adapter needs CMD_OPENF_IG_DESCCACHE flag to be set. If this flag is
not set, fw flushes the global IG desc cache. This flag is nop in older
adapter.

Also increment driver version

Signed-off-by: Govindarajulu Varadarajan <gvaradar@cisco.com>
Signed-off-by: David S. Miller <davem@davemloft.net>