ARM: OMAP2+: Fix twl section warnings related to omap_twl4030_audio_init

With the recent twl related changes we can now get:

WARNING: arch/arm/mach-omap2/built-in.o(.text+0x15f88): Section mismatch in
reference from the function sdp3430_twl_gpio_setup() to the function
.init.text:omap_twl4030_audio_init()
The function sdp3430_twl_gpio_setup() references
the function __init omap_twl4030_audio_init().
This is often because sdp3430_twl_gpio_setup lacks a __init
annotation or the annotation of omap_twl4030_audio_init is wrong.

WARNING: arch/arm/mach-omap2/built-in.o(.text+0x16968): Section mismatch in
reference from the function zoom_twl_gpio_setup() to the function
.init.text:omap_twl4030_audio_init()
The function zoom_twl_gpio_setup() references
the function __init omap_twl4030_audio_init().
This is often because zoom_twl_gpio_setup lacks a __init
annotation or the annotation of omap_twl4030_audio_init is wrong.

Fix this by removing __init from omap_twl4030_audio_init() as
suggested by Peter Ujfalusi <peter.ujfalusi@ti.com>.

Signed-off-by: Tony Lindgren <tony@atomide.com>