usb: ehci-omap: Fix PM disable depth umbalance in ehci_hcd_omap_probe

usb: ehci-omap: Fix PM disable depth umbalance in ehci_hcd_omap_probe

The pm_runtime_enable will decrement the power disable depth. Imbalance
depth will resulted in enabling runtime PM of device fails later.  Thus
a pairing decrement must be needed on the error handling path to keep it
balanced.

Fixes: 6c984b066d84b ("ARM: OMAP: USBHOST: Replace usbhs core driver APIs by Runtime pm APIs")
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Zhang Qilong <zhangqilong3@huawei.com>
Link: https://lore.kernel.org/r/20201123145719.1455849-1-zhangqilong3@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>