dt-bindings: pinctrl: k3: Introduce pinmux definitions for J721S2

dt-bindings: pinctrl: k3: Introduce pinmux definitions for J721S2

Add pinctrl macros for J721S2 SoC. These macro definitions are
similar to that of J721E, but adding new definitions to avoid
any naming confusions in the soc dts files.

checkpatch insists the following error exists:
ERROR: Macros with complex values should be enclosed in parentheses

However, we do not need parentheses enclosing the values for this
macro as we do intend it to generate two separate values as has been
done for other similar platforms.

Signed-off-by: Aswath Govindraju <a-govindraju@ti.com>