Older versions of U-Boot would pinmux the whole board, but as
the bootloader got updated, it started to only pinmux the pins
it needed, and expected Linux to configure what it needed.

Unfortunately this caused an issue with the audio, because the
mcbsp2 pins were configured in the device tree but never
referenced by the driver. When U-Boot stopped muxing the audio
pins, the audio died.

This patch adds the references to the associate the pin controller
with the mcbsp2 driver which makes audio operate again.

Fixes: 5cb8b0fa ("ARM: dts: Move most of logicpd-som-lv-37xx-devkit.dts to logicpd-som-lv-baseboard.dtsi")
Signed-off-by: Adam Ford <aford173@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>