drm/msm/dsi-staging: initialize esd completion early

Initialize esd_te_gate completion variable before enabling
esd te irq line to fix watchdogg bite.

CRs-Fixed: 2205996
Change-Id: Icd27765a996202bfd2ab83adcd6110a856278689
Signed-off-by: Vara Reddy <varar@codeaurora.org>