ARM: dts: rockchip: add labels to the timer nodes on rk3066a

While the kernel doesn't care so much right now, boot loaders like
u-boot need to refine the node on their side, so to make life easier
for everyone add the labels to the timer nodes on rk3066a.

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Link: https://lore.kernel.org/r/20210612184733.2331-1-jbx6244@gmail.com


Signed-off-by: Heiko Stuebner <heiko@sntech.de>