drm/msm/dpu: convert vsync source defines to the enum

drm/msm/dpu: convert vsync source defines to the enum

Add enum dpu_vsync_source instead of a series of defines. Use this enum
to pass vsync information.

Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/598743/
Link: https://lore.kernel.org/r/20240613-dpu-handle-te-signal-v2-2-67a0116b5366@linaro.org