USB: isp1362: move debug files from proc to debugfs

Drivers should not be putting debug files in /proc/ that is what debugfs
is for, so move the isp1362 driver's debug file to debugfs.

Reviewed-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>