arm64: dts: imx8mp: Do not reconfigure Audio PLL2 on DH i.MX8M Plus DHCOM SoM

arm64: dts: imx8mp: Do not reconfigure Audio PLL2 on DH i.MX8M Plus DHCOM SoM

The DH i.MX8M Plus DHCOM SoM uses Audio PLL2 to supply clock to CLKOUT2
output. Those clock are used to supply on-SoM TC9595 DSI-to-(e)DP bridge
with RefClk and must not be reconfigured, otherwise the bridge cannot
work correctly. Stop reconfiguring Audio PLL2 on this SoM.

Fixes: f560da940e32 ("arm64: dts: imx8mp: Initialize audio PLLs from audiomix subsystem")
Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>