drivers: soc: Fix possible APR null pointer dereference

There's a possible null pointer deference if APR open fails.
Add the fix to handle error case cleanup gracefully.

CRs-fixed: 979283
Change-Id: I4c0cc05bf08d2eae5c27a1dba0a33f4183f81cf3
Signed-off-by: Deven Patel <cdevenp@codeaurora.org>