drm/msm/dp: add logs across DP driver for ease of debugging

Add trace points across the MSM DP driver to help debug
interop issues.

Changes in v2:
 - Got rid of redundant log messages.
 - Added %#x instead of 0x%x wherever required.
 - Got rid of __func__ calls in debug messages.
 - Added newline wherever missing.

Changes in v3:
 - Got rid of redundant log messages.
 - Unstuck colon from printf specifier in various places.

Changes in v4:
 - Changed goto statement and used if else-if

Changes in v5:
 - Changed if else if statement,
   to not overwrite the ret variable multiple times.
Changes in v6:
 - Changed a wrong log message.
Signed-off-by: Maitreyee Rao <maitreye@codeaurora.org>

Link: https://lore.kernel.org/r/1627346298-11528-1-git-send-email-maitreye@codeaurora.org
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>