scsi: docs: fusion: get rid of a doc build warning

Use a table for the enum list, to avoid this warning:

	./drivers/message/fusion/mptbase.c:5058: WARNING: Definition list ends without a blank line; unexpected unindent.

Link: https://lore.kernel.org/r/9ca049c2d25689c56448afddf4f0d1e619fa87f7.1586359676.git.mchehab+huawei@kernel.org


Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>