net: hinic: make functions set_ctrl0 and set_ctrl1 static

The functions set_ctrl0 and set_ctrl1 are local to the source and do
not need to be in global scope, so make them static.

Cleans up sparse warnings:
symbol 'set_ctrl0' was not declared. Should it be static?
symbol 'set_ctrl1' was not declared. Should it be static?

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>