arm64: dts: allwinner: pinephone: Enable internal HMIC bias

Revisions 1.0 and 1.1 of the PinePhone mainboard do not have an external
resistor connecting HBIAS to MIC2P. Enable the internal resistor to
provide the necessary headeset microphone bias.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Link: https://lore.kernel.org/r/20220621035452.60272-4-samuel@sholland.org