drm/msm/dsi-staging: validate TE GPIO prior to registering IRQ

If the TE GPIO is incorrectly specified then do not register for
the TE IRQ line. Disable the TE based ESD check feature as well
since it would not be valid in this case.

Change-Id: I028fb3e8bb1f60d12c779af889cb5df11d21cca0
Signed-off-by: Aravind Venkateswaran <aravindh@codeaurora.org>
Signed-off-by: Lakshmi Narayana Kalavala <lkalaval@codeaurora.org>