arm64: dts: imx8mp-venice-gw71xx: fix TPM SPI frequency

arm64: dts: imx8mp-venice-gw71xx: fix TPM SPI frequency

The IMX8MPDS Table 37 [1] shows that the max SPI master read frequency
depends on the pins the interface is muxed behind with ECSPI2
muxed behind ECSPI2 supporting up to 25MHz.

Adjust the spi-max-frequency based on these findings.

[1] https://www.nxp.com/webapp/Download?colCode=IMX8MPIEC

Fixes: 1a8f6ff6a291 ("arm64: dts: imx8mp-venice-gw71xx: add TPM device")
Cc: stable@vger.kernel.org
Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Link: https://lore.kernel.org/stable/20250523173723.4167474-1-tharvey%40gateworks.com
Signed-off-by: Shawn Guo <shawnguo@kernel.org>