nvmem: Simplify the ->add_cells() hook

[ Upstream commit 1b7c298a ]

The layout entry is not used and will anyway be made useless by the new
layout bus infrastructure coming next, so drop it. While at it, clarify
the kdoc entry.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20231215111536.316972-5-srinivas.kandagatla@linaro.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 391b06ec ("nvmem: imx-ocotp-ele: fix MAC address byte order")
Signed-off-by: Sasha Levin <sashal@kernel.org>