USB: EHCI: ehci-mv: Fix unused assignment in mv_ehci_probe()

Delete unused initialized value, because 'retval' will be assigined
by the function mv_ehci_enable(). And delete the extra blank lines.

Signed-off-by: Zhang Shengju <zhangshengju@cmss.chinamobile.com>
Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20200508142136.4232-1-tangbin@cmss.chinamobile.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>