clk: ingenic: jz4740: Fix gating of UDC clock

The UDC clock is gated when the bit is cleared, not when it is set.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Tested-by: Artur Rojek <contact@artur-rojek.eu>
Fixes: 2b555a4b ("clk: ingenic: Add missing flag for UDC clock")
Signed-off-by: Stephen Boyd <sboyd@kernel.org>