net/mlx5: inherit master link settings for representors

net/mlx5: inherit master link settings for representors

There are some physical link settings can be queried from
Ethernet devices: link status, link speed, speed capabilities,
duplex mode, etc. These setting do not make a lot of sense for
representors due to missing physical link. The new kernel drivers
dropped query for link settings for representors causing the
ioctl call to fail. This patch adds some kind of emulation
of link settings to PMD - representors inherit the link parameters
from the master device. The actual link status (up/down)
is retrieved from the representor device.

Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
Acked-by: Shahaf Shuler <shahafs@mellanox.com>