The IMX8MP_CLK_CLKOUT2 supplies the TC9595 bridge with 13 MHz reference
clock. The IMX8MP_CLK_CLKOUT2 is supplied from IMX8MP_AUDIO_PLL2_OUT.
The IMX8MP_CLK_CLKOUT2 operates only as a power-of-two divider, and the
current 156 MHz is not power-of-two divisible to achieve 13 MHz.

To achieve 13 MHz output from IMX8MP_CLK_CLKOUT2, set IMX8MP_AUDIO_PLL2_OUT
to 208 MHz, because 208 MHz / 16 = 13 MHz.

Fixes: 20d0b83e ("arm64: dts: imx8mp: Add TC9595 bridge on DH electronics i.MX8M Plus DHCOM")
Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>