USB: Drop unnecessary continue in a few drivers

Continue is not needed at the bottom of a loop.

The semantic patch implementing this change is as follows:

@@
@@

for (...;...;...) {
   ...
   if (...) {
     ...
-   continue;
   }
}

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>