net: wwan: qcom_bam_dmux: Fix missing pm_runtime_disable()

It's important to undo pm_runtime_use_autosuspend() with
pm_runtime_dont_use_autosuspend() at driver exit time.

But the pm_runtime_disable() and pm_runtime_dont_use_autosuspend()
is missing in the error path for bam_dmux_probe(). So add it.

Found by code review. Compile-tested only.

Fixes: 21a0ffd9 ("net: wwan: Add Qualcomm BAM-DMUX WWAN network driver")
Suggested-by: Stephan Gerhold <stephan.gerhold@linaro.org>
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Reviewed-by: Stephan Gerhold <stephan.gerhold@linaro.org>
Reviewed-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>