ARM: dts: imx6q-dhcom: Fix SGTL5000 VDDIO regulator connection

ARM: dts: imx6q-dhcom: Fix SGTL5000 VDDIO regulator connection

The SGTL5000 VDDIO is connected to the PMIC SW2 output, not to
a fixed 3V3 rail. Describe this correctly in the DT.

Fixes: 52c7a088badd ("ARM: dts: imx6q: Add support for the DHCOM iMX6 SoM and PDK2")
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: Ludwig Zenz <lzenz@dh-electronics.com>
Cc: NXP Linux Team <linux-imx@nxp.com>
To: linux-arm-kernel@lists.infradead.org
Signed-off-by: Shawn Guo <shawnguo@kernel.org>