arm: dts: k3-am654: Sync IOPAD macros with Linux

arm: dts: k3-am654: Sync IOPAD macros with Linux

Transition to the IOPAD macros as used in Linux in which the pin mux
mode is specified using a dedicated parameter while also dropping the
related MUX_MODEx macros that are no longer needed. This transition
will allow us to keep both Linux and U-Boot DTS in sync more easily.
While at it also align the file name of the include file itself and
update any references accordingly.

Signed-off-by: Andreas Dannenberg <dannenberg@ti.com>
Reviewed-by: Lokesh Vutla <lokeshvutla@ti.com>