drivers: net: Mark functions as static in qlcnic_io.c

This patch marks the function qlcnic_enable_tx_intr(),
qlcnic_83xx_enable_tx_intr() and qlcnic_83xx_disable_tx_intr() in
qlcnic_io.c as static because they are not used outside this file.

Thus, it also removes the following warnings in
ethernet/qlogic/qlcnic/qlcnic_io.c:

drivers/net/ethernet/qlogic/qlcnic/qlcnic_io.c:130:13: warning: no previous prototype for ‘qlcnic_enable_tx_intr’ [-Wmissing-prototypes]
drivers/net/ethernet/qlogic/qlcnic/qlcnic_io.c:147:13: warning: no previous prototype for ‘qlcnic_83xx_enable_tx_intr’ [-Wmissing-prototypes]
drivers/net/ethernet/qlogic/qlcnic/qlcnic_io.c:153:13: warning: no previous prototype for ‘qlcnic_83xx_disable_tx_intr’ [-Wmissing-prototypes]

Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: David S. Miller <davem@davemloft.net>