gve: Remove the exporting of gve_probe

The function gve_probe is declared static and marked EXPORT_SYMBOL, which
is at best an odd combination. Because the function is not used outside of
the drivers/net/ethernet/google/gve/gve_main.c file it is defined in, this
commit removes the EXPORT_SYMBOL() marking.

Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>