Several includes are not needed, so drop them.

of_platform.h is not needed, but it implicitly includes of.h which is
needed.
Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20230803-dt-header-cleanups-for-soc-v2-12-d8de2cc88bff@kernel.orgSigned-off-by: Arnd Bergmann <arnd@arndb.de>