arm64: dts: apple: t6002: Fix GPU power domains

On t6002 (M1 Ultra), each die contains a self-contained GPU block.
However, only the coprocessor and global management circuitry of the
first die are used. This is what is represented by the "gpu" PS (the
one in die1 is disabled). Nonetheless, this shared component drives the
processing blocks in both dies, and therefore depends on the AFR fabric
being powered up on both dies.

Add an explicit dependency from the GPU block on die0 to AFR on die1,
next to the existing die0 AFR dependency.

Fixes: fa86294eb355 ("arm64: dts: apple: Add initial t6000/t6001/t6002 DTs")
Signed-off-by: Asahi Lina <lina@asahilina.net>
Reviewed-by: Janne Grunau <j@jannau.net>
Signed-off-by: Hector Martin <marcan@marcan.st>