arm64: dts: mediatek: mt8195: Fix GPU thermal zone name for SVS

This SoC has two GPU related thermal zones: the primary zone must be
called "gpu-thermal" for SVS to pick it up.

Fixes: 1e5b6725 ("arm64: dts: mediatek: mt8195: Add AP domain thermal zones")
Link: https://lore.kernel.org/r/20240410083002.1357857-2-angelogioacchino.delregno@collabora.com


Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>