[SCSI] target: Fix FILEIO fd_buffered_io= token typo

This patch fixes a token typo for the TCM/FILEIO match_table_t used
for toggling O_SYNC usage for individual struct file backend access.

Reported-by: Christophe Fergeau <cfergeau@gmail.com>
Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>