net: ena: Make some functions static

net: ena: Make some functions static

BugLink: https://bugs.launchpad.net/bugs/1890845
commit 32109c7065a2dd9382d77706486cfd5d0cf700d2 upstream.

Fix sparse warnings:

drivers/net/ethernet/amazon/ena/ena_netdev.c:460:6: warning: symbol 'ena_xdp_exchange_program_rx_in_range' was not declared. Should it be static?
drivers/net/ethernet/amazon/ena/ena_netdev.c:481:6: warning: symbol 'ena_xdp_exchange_program' was not declared. Should it be static?
drivers/net/ethernet/amazon/ena/ena_netdev.c:1555:5: warning: symbol 'ena_xdp_handle_buff' was not declared. Should it be static?

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Ian May <ian.may@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>