arm64: dts: rockchip: update px30 thermal zones for GPU

Without the trips, the following errors are received in the dmesg
log and the rockchip-thermal driver fails to load the gpu sensor:

"thermal_sys: Failed to find 'trips' node"
"rockchip-thermal ff280000.tsadc: failed to register sensor 1: -22"

Trip values are assumed, unfortunately, as the same values as the
CPU. The datasheet and TRM didn't appear to have any information
regarding thermals for the GPU.

Stress tested successfully on my Odroid Go Advance.

Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
Link: https://lore.kernel.org/r/20221201203655.1245-4-macroalpha82@gmail.com


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