board: ls1043rdb: Move USB muxing config to config_board_mux

Pin-muxing code should be in config_board_mux, move USB muxing
config to config_board_mux.

Signed-off-by: Zhao Qiang <qiang.zhao@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>
1 file changed