dmaengine: stm32-dmamux: Fix PM disable depth imbalance in stm32_dmamux_probe

The pm_runtime_enable will increase power disable depth.
If the probe fails, we should use pm_runtime_disable() to balance
pm_runtime_enable().

Fixes: 4f3ceca2

 ("dmaengine: stm32-dmamux: Add PM Runtime support")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Reviewed-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Link: https://lore.kernel.org/r/20220108085336.11992-1-linmq006@gmail.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>