net: thunderx: move link state polling function to VF

Move the link change polling task to VF side in order to
prevent races between VF and PF while sending link change
message(s). This commit is to implement link change request
to be initiated by VF.

Signed-off-by: Vadim Lomovtsev <vlomovtsev@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>