staging: lustre: osc: Make osc_init() static

osc_init() is marked as the module_init function in osc_request.c
and is never used anywhere else. Hence, it can (and should) be
declared static.

sparse also complained about this with the following warning, which
is fixed by this patch.

andreas@workbox:~/linux-next$ make C=1 M=drivers/staging/lustre/lustre/osc/
[...]
drivers/staging/lustre/lustre/osc/osc_request.c:3335:12: warning:
symbol 'osc_init' was not declared. Should it be static?
[...]

Signed-off-by: Andreas Ruprecht <rupran@einserver.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>