RDMA/uverbs: Add support for UCAPs in context creation

RDMA/uverbs: Add support for UCAPs in context creation

Add support for file descriptor array attribute for GET_CONTEXT
commands.

Check that the file descriptor (fd) array represents fds for valid UCAPs.
Store the enabled UCAPs from the fd array as a bitmask in ib_ucontext.

Signed-off-by: Chiara Meiohas <cmeiohas@nvidia.com>
Link: https://patch.msgid.link/ebfb30bc947e2259b193c96a319c80e82599045b.1741261611.git.leon@kernel.org
Reviewed-by: Yishai Hadas <yishaih@nvidia.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>