ASoC: msm: qdsp6v2: Fix return code check in adm driver

Return error only if apr_send_pkt() function
return code is less than 0.

CRs-Fixed: 2262017
Change-Id: I98903c6c275f360d32c3af523352071d92d1ef85
Signed-off-by: Aditya Bavanari <abavanar@codeaurora.org>