ARM: omap: preemptively fix section mismatch in omap4_sdp4430_wifi_mux_init()

Found by review.

omap4_sdp4430_wifi_mux_init() is called by an __init marked function,
and only calls omap_mux_init_gpio() and omap_mux_init_signal() which
are both also an __init marked functions.

The only reason this doesn't issue a warning is because the compiler
inlines omap4_sdp4430_wifi_mux_init() into omap4_sdp4430_wifi_init().

So, lets add the __init annotation to ensure this remains safe should
the compiler choose not to inline.
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mach-omap2/board-4430sdp.c

@@ -851,7 +851,7 @@ static struct omap_board_mux board_mux[] __initdata = {
 #define board_mux	NULL
  #endif
 
-static void omap4_sdp4430_wifi_mux_init(void)
+static void __init omap4_sdp4430_wifi_mux_init(void)
 {
 	omap_mux_init_gpio(GPIO_WIFI_IRQ, OMAP_PIN_INPUT |
 				OMAP_PIN_OFF_WAKEUPENABLE);