OMAP3: am3517crane: remove NULL board_mux from board file

Since 7203f8a4 (arm: mach-omap2: remove
NULL board_mux from board files) NULL board_mux is defined in mux.h.
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/board-am3517crane.c

@@ -45,8 +45,6 @@ static struct omap_board_config_kernel am3517_crane_config[] __initdata = {
 static struct omap_board_mux board_mux[] __initdata = {
 	{ .reg_offset = OMAP_MUX_TERMINATOR },
 };
-#else
-#define board_mux	NULL
 #endif
 
 static void __init am3517_crane_init_early(void)