usb: ehci-exynos: Return immediately from suspend if ehci_suspend fails

Patch 'b8efdafb USB: EHCI: add check for wakeup/suspend race'
adds a check for possible race between suspend and wakeup interrupt,
and thereby it returns -EBUSY as error code if there's a wakeup
interrupt.
So the platform host controller should not proceed further with
its suspend callback, rather should return immediately to avoid
powering down the essential things, like phy.

Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
Acked-by: Jingoo Han <jg1.han@samsung.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>