disp: msm: sde: avoid rc restart when triggered from panel dead

This change prevents scheduling of rc_restart in case of
panel dead. This early return is required to avoid the list
add corruption when a race condition happens between event
thread and commit thread. When event thread is handling
display failure notification if the virt_enable arrives in
commit thread it will reinizialize kthread for
delayed_off_work without deactivating the existing list
which leads to linkage corruption.

Change-Id: I41d08cd47ba6f887f0860e52bcddf414085524bb
Signed-off-by: Mahadevan <mahap@codeaurora.org>