dt-bindings: mux: Remove nodename pattern constraints

dt-bindings: mux: Remove nodename pattern constraints

The nodename pattern in  created an unnecessary restriction that forced
all mux nodes to be named with the 'mux-controller' prefix.
This prevented valid use cases where mux functionality is part of other
hardware blocks that should use more specific naming conventions.

Remove the $nodename pattern constraints from both the 'select' keyword
and the properties section of the mux-controller schema.

Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
Link: https://patch.msgid.link/dbe73c0777eca61cf14442f4082caae62b61805a.1769703480.git.tommaso.merciai.xr@bp.renesas.com
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>