net/sfc: request MAC stats upload immediately on port start

net/sfc: request MAC stats upload immediately on port start

If MAC stats refresh is arranged to be done by periodic DMA,
the first DMA transaction is unlikely to occur right on the
port start; if the user tries to get stats right after port
start and before the transaction occurs, bogus figures will
be collected; a one-off stats upload on port start is a fix

Fixes: 1caab2f1e684 ("net/sfc: add basic statistics")
Cc: stable@dpdk.org
Signed-off-by: Ivan Malov <ivan.malov@oktetlabs.ru>
Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>