staging/ozwpan: Mark local functions as static (fix sparse warnings)

sparse complains about the following functions

ozhcd.c:330:20: warning: symbol 'oz_uncancel_urb' was not declared.  Should it be static?
ozhcd.c:420:6: warning: symbol 'oz_complete_buffered_urb' was not declared. Should it be static?
ozmain.c:25:6: warning: symbol 'g_net_dev' was not declared. Should it be static?
ozevent.c:95:5: warning: symbol 'oz_events_open' was not declared.  Should it be static?
ozevent.c:110:5: warning: symbol 'oz_events_release' was not declared.  Should it be static?
ozevent.c:121:9: warning: symbol 'oz_events_read' was not declared.  Should it be static?
ozevent.c:160:30: warning: symbol 'oz_events_fops' was not declared.  Should it be static?
ozcdev.c:47:14: warning: symbol 'g_oz_class' was not declared. Should it be static?
ozcdev.c:74:5: warning: symbol 'oz_cdev_open' was not declared. Should it be static?
ozcdev.c:86:5: warning: symbol 'oz_cdev_release' was not declared.  Should it be static?
ozcdev.c:94:9: warning: symbol 'oz_cdev_read' was not declared. Should it be static?
ozcdev.c:146:9: warning: symbol 'oz_cdev_write' was not declared. Should it be static?
ozcdev.c:236:6: warning: symbol 'oz_cdev_ioctl' was not declared. Should it be static?
ozcdev.c:300:14: warning: symbol 'oz_cdev_poll' was not declared. Should it be static?
ozcdev.c:321:30: warning: symbol 'oz_fops' was not declared. Should it be static?
ozproto.c:958:6: warning: context imbalance in 'oz_polling_lock_bh' - wrong count at exit
ozproto.c:964:6: warning: context imbalance in 'oz_polling_unlock_bh' - unexpected unlock
ozusbsvc1.c:308:6: warning: symbol 'oz_usb_handle_ep_data' was not declared. Should it be static?
ozpd.c:410:6: warning: symbol 'oz_set_more_bit' was not declared. Should it be static?
ozpd.c:418:6: warning: symbol 'oz_set_last_pkt_nb' was not declared.  Should it be static?

-> add static keyword to silence the warning and make sparse happy.

Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>