ASoC: msm: qdsp6v2: check param length for EAC3 format

Initialize param length with user space argument and
check the condition for maximum length in
SND_AUDIOCODEC_EAC3 format.

BUG 28868303

Change-Id: I1d139a5342c35434651ce617b3a4fd2c231574fb
Signed-off-by: vivek mehta <mvivek@codeaurora.org>