scsi: target: target_core_transport.c: fix kernel-doc warnings

Correct a function parameter's name to eliminate kernel-doc warnings
in drivers/target/target_core_transport.c.

Fixes these kernel-doc warnings: (tested by adding these files to a new
target.rst documentation file)

../drivers/target/target_core_transport.c:1671: warning: No description found for parameter 'fabric_tmr_ptr'
../drivers/target/target_core_transport.c:1671: warning: Excess function parameter 'fabric_context' description in 'target_submit_tmr'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
To: "Nicholas A. Bellinger" <nab@linux-iscsi.org>
Cc: linux-scsi@vger.kernel.org
Cc: target-devel@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Cc: "James E.J. Bottomley" <jejb@linux.vnet.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>