IB/core: Release allocated memory in cache setup failure

The failure in ib_cache_setup_one function during
ib_register_device will leave leaked allocated memory.

Fixes: 03db3a2d ("IB/core: Add RoCE GID table management")
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>