ARM: dts: imx7-tqma7: Fix PMIC v33 rail voltage range

regulator-*-microvolt is not the range the regulator supports, but the
range which the regulator is allowed to configure. Limit v33 rail to
3.3V only.

Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>