arm64: dts: mediatek: Correct SPI clock of MT8192

arm64: dts: mediatek: Correct SPI clock of MT8192

When the initial devicetree for mt8192 was added in 92c8d173a270 ("arm64:
dts: Add Mediatek SoC MT8192 and evaluation board dts and Makefile"), the
clock driver for mt8192 was not yet upstream, so the clock property nodes
were set to the clk26m clock as a placeholder.

Given that the clock driver has since been added through 73cb537cf192 ("clk:
mediatek: Add MT8192 basic clocks support"), as well as its dt-bindings
through 85921f3903eb ("clk: mediatek: Add dt-bindings of MT8192 clocks") and
devicetree nodes through ebf68a21692d ("arm64: dts: mediatek: Add mt8192
clock controllers"), fix the SPI clock property to point to the actual
clock.

Signed-off-by: Allen-KH Cheng <Allen-KH.Cheng@mediatek.com>
Reviewed-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20220113065822.11809-3-allen-kh.cheng@mediatek.com
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>