clk: msm: clock-gcc-8996: Add USB_20_BCR

Add the BCR to reset USB20 block to gcc_usb20_master_clk. This will
allow the driver to correctly call clk_reset().

Change-Id: Ib4f8b73317032c88f5272a530007ff08d14dbd4a
Signed-off-by: Jack Pham <jackp@codeaurora.org>