USB: OHCI: fix bugs in debug routines

commit 256dbcd8 upstream.

The debug routine fill_async_buffer() in ohci-hcd is buggy: It never
produces any output because it forgets to initialize the output buffer
size.  Also, the debug routine ohci_dump() has an unused argument.

This patch adds the correct initialization and removes the unused
argument.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>