ARM: dts: imx6: RDU2: bump SoC/PU operating points by 25mV

This bumps the SoC/PU domain operating points by 25mV, giving a total
of 75mV margin to the minimum required voltages. This gets rid of
brown-outs seen due to voltage drop-out on the board.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Tested-by: Chris Healy <cphealy@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>