uio: fix some kernel-doc markups

The definitions for (devm_)uio_register_device should be
at the header file, as the macros are there. The ones
inside uio.c refer, instead, to __(devm_)uio_register_device.

Update them and add new kernel-doc markups for the macros.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/82ab7b68d271aeda7396e369ff8a629491b9d628.1603469755.git.mchehab+huawei@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>