ARM: imx: remove header file mach/irqs.h

The only mach/irqs.h user outside arch/arm/mach-imx is
sound/soc/fsl/imx-pcm-fiq.c, which refers to mxc_set_irq_fiq().
Move the declaration into include/linux/platform_data/asoc-imx-ssi.h,
so that we can remove mach/irqs.h includsion from imx-pcm-fiq.c.

Inside arch/arm/mach-imx, the only users to mach/irqs.h are avic.c
and tzic.c for referring to macro FIQ_START.  Let's move the macro
into irq-common.h and get rid of mach/irqs.h completely.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: alsa-devel@alsa-project.org