drm/msm/dsi-staging: avoid out of bounds access of ctrl array

To avoid out of bounds access of ctrl array, an extra check
against maximum possible value is required. This is implemented in the
new macro display_for_each_ctrl.

Change-Id: I1511392f72df2faf9464d815810c8615925127fd
Signed-off-by: Satya Rama Aditya Pinapala <psraditya30@codeaurora.org>