ARM: imx: iomux-v1.h: Fix build error due to __init annotation

Fix the following build error found when building imx_v4_v5_defconfig:

  CC      arch/arm/mach-imx/mach-imx27ipcam.o
In file included from arch/arm/plat-mxc/include/mach/iomux-mx27.h:23,
                 from arch/arm/mach-imx/mach-imx27ipcam.c:22:
arch/arm/plat-mxc/include/mach/iomux-v1.h:99: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'imx_iomuxv1_init'

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>