arm64: dts: imx8mm: fix voltage for 1.6GHz CPU operating point

The datasheet for both the industrial and consumer variant of the
SoC lists a typical voltage of 0.95V for the 1.6GHz CPU operating
point.

Fixes: e85c9d0f (arm64: dts: imx8mm: Add cpufreq properties)
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>