usb: chipidea: udc: remove redundant assignment to variable retval

usb: chipidea: udc: remove redundant assignment to variable retval

The variable retval is being initialized with a value that is never
read and it is being updated later with a new value. The
initialization is redundant and can be removed.  Also remove a blank
line.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20190704150341.759-1-colin.king@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>