[PATCH] splice: pass offset around for ->splice_read() and ->splice_write()

[PATCH] splice: pass offset around for ->splice_read() and ->splice_write()

We need not use ->f_pos as the offset for the file input/output. If the
user passed an offset pointer in through sys_splice(), just use that and
leave ->f_pos alone.

Signed-off-by: Jens Axboe <axboe@suse.de>