Revert "ASoC: fsl: fix multiple definition of init_module"

This reverts commit 25b8d314.

While the commit fixes multiple init_module definition error with
module build, it breaks build when both imx-pcm-fiq and imx-pcm-dma
are built in as below.

  LD      sound/soc/fsl/snd-soc-fsl-ssi.o
  LD      sound/soc/fsl/snd-soc-fsl-utils.o
  LD      sound/soc/fsl/snd-soc-imx-ssi.o
  LD      sound/soc/fsl/snd-soc-imx-audmux.o
  LD      sound/soc/fsl/snd-soc-imx-pcm-fiq.o
  LD      sound/soc/fsl/snd-soc-imx-pcm-dma.o
  LD      sound/soc/fsl/snd-soc-eukrea-tlv320.o
  LD      sound/soc/fsl/snd-soc-imx-sgtl5000.o
  LD      sound/soc/fsl/snd-soc-imx-mc13783.o
  LD      sound/soc/fsl/built-in.o
sound/soc/fsl/snd-soc-imx-pcm-dma.o: In function `imx_pcm_free':
imx-pcm.c:(.text+0x464): multiple definition of `imx_pcm_free'
sound/soc/fsl/snd-soc-imx-pcm-fiq.o:imx-pcm-fiq.c:(.text+0x1a8): first defined here
sound/soc/fsl/snd-soc-imx-pcm-dma.o: In function `snd_imx_pcm_mmap':
imx-pcm.c:(.text+0x35c): multiple definition of `snd_imx_pcm_mmap'
sound/soc/fsl/snd-soc-imx-pcm-fiq.o:imx-pcm-fiq.c:(.text+0xa0): first defined here
sound/soc/fsl/snd-soc-imx-pcm-dma.o: In function `imx_pcm_new':
imx-pcm.c:(.text+0x3dc): multiple definition of `imx_pcm_new'
sound/soc/fsl/snd-soc-imx-pcm-fiq.o:imx-pcm-fiq.c:(.text+0x120): first defined here
make[4]: *** [sound/soc/fsl/built-in.o] Error 1

Let's revert the commit and find a proper fix for multiple init_module
definition error later.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>