ath10k: fix error return code in ahb

Fix to return a negative error code from the error handling case
instead of 0, as done elsewhere in function ath10k_ahb_probe() or
ath10k_ahb_resource_init().

Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>