USB: musb: fix indentation issue on a return statement

A return statement is indented one level too far, fix this by removing
a tab.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>