ARM: OMAP2+: Fix board_mux section type conflict when OMAP_MUX is not set

Otherwise we can get:

arch/arm/mach-omap2/mux.h:249:31: error: board_mux causes a section type conflict

Signed-off-by: Tony Lindgren <tony@atomide.com>
diff --git a/arch/arm/mach-omap2/mux.h b/arch/arm/mach-omap2/mux.h
index 2132308..69fe060 100644
--- a/arch/arm/mach-omap2/mux.h
+++ b/arch/arm/mach-omap2/mux.h
@@ -246,7 +246,7 @@
 {
 }
 
-static struct omap_board_mux *board_mux __initdata __maybe_unused;
+static struct omap_board_mux *board_mux __maybe_unused;
 
 #endif