IB/qedr: Fix fall-through warnings for Clang

In preparation to enable -Wimplicit-fallthrough for Clang, fix a warning
by explicitly adding a break statement instead of just letting the code
fall through to the next case.

Link: https://lore.kernel.org/r/8d7cf00ec3a4b27a895534e02077c2c9ed8a5f8e.1605896059.git.gustavoars@kernel.org
Link: https://github.com/KSPP/linux/issues/115


Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Acked-by: Michal <Kalderon &lt;michal.kalderon@marvell.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>