paging: paging_flush_bts: be sure pending_requests is initalized

The BSSMAP reset causes the paging requests to be flushed. When
this happens right after startup then calling paging_flush_bts()
may be called when the list bts->paging.pending_requests is not
yet initalized, which causes a segfault.

Call paging_init_if_needed() to be sure that the list is
inizalized (like the other functions also do)

Change-Id: I42ddbfdec6f9d74d858ad13cc38b5b64061d08dc
1 file changed