phy: ti: Add missing pm_runtime_disable() in serdes_am654_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().
Add missing pm_runtime_disable() for serdes_am654_probe().

Fixes: 71e2f5c5

 ("phy: ti: Add a new SERDES driver for TI's AM654x SoC")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Link: https://lore.kernel.org/r/20220301025853.1911-1-linmq006@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>