ASoC: msm: q6: check upper bounds when copy ac3 params

Although AC3 maximum param size is fixed, better check upper bounds
when copy user data. It might cause overflow, possibly cause memory
corruption.

Change-Id: I2f7cec8edd9e013de1433ea06480b963ec307196
Signed-off-by: Fred Oh <fred@codeaurora.org>
Signed-off-by: flar2 <asegaert@gmail.com>