mfd: simple-mfd-i2c: Add compatible strings for Layerscape QIXIS FPGA

mfd: simple-mfd-i2c: Add compatible strings for Layerscape QIXIS FPGA

The QIXIS FPGA found on Layerscape boards such as LX2160AQDS, LS1028AQDS
etc deals with power-on-reset timing, muxing etc. Use the simple-mfd-i2c
as its core driver by adding its compatible string (already found in
some dt files). By using the simple-mfd-i2c driver, any child device
will have access to the i2c regmap created by it.

Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Link: https://lore.kernel.org/r/20250707153120.1371719-1-ioana.ciornei@nxp.com
Signed-off-by: Lee Jones <lee@kernel.org>