drm/msm/dp: Use devres for ioremap()

drm/msm/dp: Use devres for ioremap()

The non-devres version of ioremap is used, which requires manual
cleanup. But the code paths leading here is mixed with other devres
users, so rely on this for ioremap as well to simplify the code.

Reviewed-by: Abhinav Kumar <abhinavk@codeaurora.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20211001174400.981707-3-bjorn.andersson@linaro.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>