drivers: net: Mark functions as static in qlcnic_83xx_hw.c

This patch marks the function qlcnic_83xx_clear_legacy_intr_mask(),
qlcnic_83xx_set_legacy_intr_mask() and
qlcnic_83xx_enable_legacy_msix_mbx_intr() in qlcnic_83xx_hw.c as static
because they are not used outside this file.

Thus, it also removes the following warnings
in ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c:

drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c:318:13: warning: no previous prototype for ‘qlcnic_83xx_clear_legacy_intr_mask’ [-Wmissing-prototypes]
drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c:323:13: warning: no previous prototype for ‘qlcnic_83xx_set_legacy_intr_mask’ [-Wmissing-prototypes]
drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c:343:13: warning: no previous prototype for ‘qlcnic_83xx_enable_legacy_msix_mbx_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>