drm/msm/dpu: Add dpu_hw_cwb abstraction for CWB block

The CWB mux has its own registers and set of operations. Add dpu_hw_cwb
abstraction to allow driver to configure the CWB mux.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Jessica Zhang <quic_jesszhan@quicinc.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/629254/
Link: https://lore.kernel.org/r/20241216-concurrent-wb-v4-12-fe220297a7f0@quicinc.com


[DB: added #include <linux/bitfield.h>]
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>