drm/msm/mdp5: add perf blocks for holding fudge factors

Prior downstream kernels had "fudge factors" in devicetree which would
be applied to things like interconnect bandwidth calculations. Bring
some of those values back here.

Signed-off-by: James Willcox <jwillcox@squareup.com>
[DB: changed _ff to _inefficiency, fixed patch description]
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20210525131316.3117809-7-dmitry.baryshkov@linaro.org


Signed-off-by: Rob Clark <robdclark@chromium.org>