ARM: dts: imx6qdl-apalis/-colibri: fix on-module regulators

ARM: dts: imx6qdl-apalis/-colibri: fix on-module regulators

Remove the 2.5V regulator, it does not exist. There is 3.3V and
3.3V_AUDIO provided to the module through the edge connector,
model those as fixed regulators like we use to do in other
Colibri device trees. The SGTL5000 uses 3.3V_AUDIO as VDDA. Note
that the driver derives the analog ground voltage (VAG) from this
supply. The new value should allow higher output swings before
clipping occurs. Refer to the SGTL5000 datasheet for details.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>