drivers: soc: put APR Tx buffer back into queue in error scenario

When underlying channel fails to send the APR buffer to the remote
end, APR should put the Tx buffer back into queue to avoid memory
leak.

CRs-fixed: 979283
Change-Id: I4f94daa3c9be748a30d532cf9cc8f3aa2284c060
Signed-off-by: Deven Patel <cdevenp@codeaurora.org>