USB: idmouse: clean up runaway white space

Drop space between function identifiers and opening parenthesis, which
was no longer even used consistently within the driver.

Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20191105103638.4929-4-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>