bcm63268-timer-clocks have been sent upstream with a positive review, so let's
add them to pending v5.15.
Also add devm_clk_hw_register_gate() patch from v5.17 to backports since it's
needed for upstream bcm63268-timer-clocks patches.
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
