of: Move of_device_get_match_data() declaration

of_device.h mostly defines functions for bus drivers whereas
of_device_get_match_data() is used by drivers. Let's move it to of.h.

Link: https://lore.kernel.org/r/20230329-dt-cpu-header-cleanups-v1-3-581e2605fe47@kernel.org


Signed-off-by: Rob Herring <robh@kernel.org>