ARM: dts: imx6dl-sabreauto: update opp table for auto part

Update i.MX6DL automotive part's opp table according to i.MX6DL
automotive datasheet Rev.9, 11/2018, it adds 996MHz set-point
support as below:

LDO enabled(min value):
996MHz: VDDARM: 1.275V, VDDSOC: 1.175V;
792MHz: VDDARM: 1.150V, VDDSOC: 1.150V;
396MHz: VDDARM: 1.125V, VDDSOC: 1.150V;

Adding 25mV to cover board IR drop, for LDO enabled mode of 996MHz,
as the max value of LDO output can NOT exceed 1.3V, so 25mV is NOT
added for VDDARM.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>