arm64: dts: mt8183: Fix Mali GPU clock

The actual clock feeding into the Mali GPU on the MT8183 is from the
clock gate in the MFGCFG block, not CLK_TOP_MFGPLL_CK from the TOPCKGEN
block, which itself is simply a pass-through placeholder for the MFGPLL
in the APMIXEDSYS block.

Fix the hardware description with the correct clock reference.

Fixes: a8168ceb ("arm64: dts: mt8183: Add node for the Mali GPU")
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Link: https://lore.kernel.org/r/20220927101128.44758-2-angelogioacchino.delregno@collabora.com


Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>