dt-bindings: i2c: imx-lpi2c: add i.MX94 LPI2C

Add compatible string "fsl,imx94-lpi2c" for the i.MX94 chip, which is
backward compatible with i.MX7ULP. Set it to fall back to
"fsl,imx7ulp-lpi2c".

Signed-off-by: Frank Li <Frank.Li@nxp.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20250306155815.110514-1-Frank.Li@nxp.com