UPSTREAM: usb: musb: Fix an error message

'ret' is known to be 0 here.
Initialize 'ret' with the expected error code before using it.

Bug: 254441685
Fixes: 0990366bab3c ("usb: musb: Add support for MediaTek musb controller")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/69f514dc7134e3c917cad208e73cc650cb9e2bd6.1620159879.git.christophe.jaillet@wanadoo.fr


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit d9ff1096a840dddea3d5cfa2149ff7da9f499fb2)
Signed-off-by: Lee Jones <joneslee@google.com>
Change-Id: Ie8e61c7a7e2db801c741b4ed17e7bdcfccc73347