phy: rockchip-inno-usb2: Do not lock in bvalid IRQ handler

Clearing the IRQ is atomic, so there is no need to hold the mutex.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Tested-by: Michael Riesch <michael.riesch@wolfvision.net>
Link: https://lore.kernel.org/r/20220414032258.40984-4-samuel@sholland.org


Signed-off-by: Vinod Koul <vkoul@kernel.org>