USB: Speedtouch: add pre_reset and post_reset routines

This patch (as1150) fixes a problem in the speedtch driver.  When it
resets the modem during probe it will be unbound from the other
interfaces it has claimed, because it doesn't define a pre_reset and a
post_reset method.

The patch defines "do-nothing" methods.  This fixes Bugzilla #11767.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>