IB: Fix some documentation warnings

Parsing verbs.c with kernel-doc produce some warnings:

	./drivers/infiniband/core/verbs.c:2579: WARNING: Unexpected indentation.
	./drivers/infiniband/core/verbs.c:2581: WARNING: Block quote ends without a blank line; unexpected unindent.
	./drivers/infiniband/core/verbs.c:2613: WARNING: Unexpected indentation.
	./drivers/infiniband/core/verbs.c:2579: WARNING: Unexpected indentation.
	./drivers/infiniband/core/verbs.c:2581: WARNING: Block quote ends without a blank line; unexpected unindent.
	./drivers/infiniband/core/verbs.c:2613: WARNING: Unexpected indentation.

Address them by adding an extra blank line and converting the parameters
on one of the arguments to a table.

Link: https://lore.kernel.org/r/4c5466d0f450c5a9952138150c3485740b37f9c5.1586881715.git.mchehab+huawei@kernel.org


Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>