arm64: dts: imx95: Use GPU_CGC as core clock for GPU

arm64: dts: imx95: Use GPU_CGC as core clock for GPU

The i.MX95 imx-sm introduced new GPU_CGC clock since imx-sm commit
ca5e078833fa ("SM-128: Add clock management via CCM LPCG direct control")
which are downstream clock of GPU clock. These new GPU_CGC clock
gate the existing GPU clock. Currently, without clk_ignore_unused
on kernel command line, those new GPU_CGC clock are unused and the
kernel will disable them. This has no impact on i.MX95 A0/A1, but
does prevent GPU register access from working at all on i.MX95 B0.
The GPU_CGC clock are present on both i.MX95 A0/A1/B0, therefore
update the DT such, that the GPU core clock are the GPU_CGC clock.
When the panthor driver enables the GPU core clock, it enables both
the GPU_CGC as well as its parent GPU clock.

Fixes: 67934f248e64 ("arm64: dts: imx95: Describe Mali G310 GPU")
Signed-off-by: Marek Vasut <marek.vasut@mailbox.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>