spmi: rename spmi device lookup helper

Rename the SPMI device helper which is used to lookup a device from its
OF node as spmi_find_device_by_of_node() so that it reflects the
implementation and matches how other helpers like this are named.

This will specifically make it more clear that this is a lookup function
which returns a reference counted structure.

Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20231003152927.15000-6-johan+linaro@kernel.org


Signed-off-by: Lee Jones <lee@kernel.org>