arm64: dts: ti: k3-j722s-main: fix the audio refclk source

arm64: dts: ti: k3-j722s-main: fix the audio refclk source

At the moment the clock parent of the audio extclk output is PLL1_HSDIV6
of the main domain. This very clock output is also used among various IP
cores, for example for the USB1 LPM clock. The audio extclock being an
external clock output with a variable frequency, it is likely that a
user of this clock will try to set it's frequency to a different value,
i.e. an audio codec. Because that clock output is used also for other IP
cores, bad things will happen.

Instead of using PLL1_HSDIV6 use the PLL2_HSDIV8 as a sane default, as
this output is exclusively used among other audio peripherals.

Signed-off-by: Michael Walle <mwalle@kernel.org>
Link: https://patch.msgid.link/20251017102228.530517-2-mwalle@kernel.org
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>