net: gve: convert strlcpy to strscpy

Usage of strlcpy in linux kernel has been recently deprecated[1], so
convert gve driver to strscpy

[1] https://lore.kernel.org/lkml/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL
=V6A6G1oUZcprmknw@mail.gmail.com/

Signed-off-by: Daode Huang <huangdaode@huawei.com>
Reviewed-by: Catherine Sullivan <csully@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>