imx: kontron-sl-mx8mm: Use voltage rail names from schematic for PMIC regulator-names

Improve the naming of the regulators to contain the voltage rail
names from the schematic.

Suggested-by: Heiko Thiery <heiko.thiery@gmail.com>
Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Reviewed-by: Fabio Estevam <festevam@denx.de>
1 file changed