ath11k: fix error code in ath11k_qmi_assign_target_mem_chunk()

The "ret" vairable is not set at this point.  It could be uninitialized
or zero.  The correct thing to return is -ENODEV.

Fixes: 6ac04bdc ("ath11k: Use reserved host DDR addresses from DT for PCI devices")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20220111071445.GA11243@kili