drivers: sbe-2t3e3: Mark functions as static in ctrl.c

drivers: sbe-2t3e3: Mark functions as static in ctrl.c

Mark functions t3e3_set_loopback(), t3e3_reg_read(), t3e3_reg_write(),
t3e3_port_get(), t3e3_port_set(), t3e3_port_get_stats() and
t3e3_port_del_stats() as static in ctrl.c because they are not used
outside this file.

This eliminates the following warnings in ctrl.c:
drivers/staging/sbe-2t3e3/ctrl.c:34:6: warning: no previous prototype for ‘t3e3_set_loopback’ [-Wmissing-prototypes]
drivers/staging/sbe-2t3e3/ctrl.c:98:6: warning: no previous prototype for ‘t3e3_reg_read’ [-Wmissing-prototypes]
drivers/staging/sbe-2t3e3/ctrl.c:135:6: warning: no previous prototype for ‘t3e3_reg_write’ [-Wmissing-prototypes]
drivers/staging/sbe-2t3e3/ctrl.c:167:6: warning: no previous prototype for ‘t3e3_port_get’ [-Wmissing-prototypes]
drivers/staging/sbe-2t3e3/ctrl.c:172:6: warning: no previous prototype for ‘t3e3_port_set’ [-Wmissing-prototypes]
drivers/staging/sbe-2t3e3/ctrl.c:219:6: warning: no previous prototype for ‘t3e3_port_get_stats’ [-Wmissing-prototypes]
drivers/staging/sbe-2t3e3/ctrl.c:285:6: warning: no previous prototype for ‘t3e3_port_del_stats’ [-Wmissing-prototypes]

Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>