arm64: dts: lx2160a: change i2c0 (iic1) pinmux mask to one bit

arm64: dts: lx2160a: change i2c0 (iic1) pinmux mask to one bit

LX2160A pinmux is done in groups by various length bitfields within
configuration registers.

The first i2c bus (called IIC1 in reference manual) is configured through
field IIC1_PMUX in register RCWSR14 bit 10 which is described in the
reference manual as a single bit, unlike the other i2c buses.

Change the bitmask for the pinmux nodes from 0x7 to 0x1 to ensure only
single bit is modified.

Further change the zero in the same line to hexadecimal format for
consistency.

Align with documentation by avoiding writes to reserved bits. No functional
change, as writing the extra two reserved bits is not known to cause
issues.

Fixes: 8a1365c7bbc1 ("arm64: dts: lx2160a: add pinmux and i2c gpio to support bus recovery")
Signed-off-by: Josua Mayer <josua@solid-run.com>
Signed-off-by: Frank Li <Frank.Li@nxp.com>