ALSA: sound/arm: Fix build failure caused by missing struct aaci definition

This patch fixes a build failure introduced by the patch
  ALSA: AACI: factor common hw_params logic into aaci_pcm_hw_params [1]
by adding/moving the aaci struct to the right position.

The patch mentioned above merged common source parts into one function,
but unfortunately left out the aaci struct and consequently caused a
build failure e.g. for arm versatile_config [2]

References:
[1] http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=d3aee799


[2] http://kisskb.ellerman.id.au/kisskb/buildresult/1893605/

Patch against Linus' tree.

Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>