msm: kgsl: Add a flag to context struct for bad timestamp waits

If the userspace calls the waittimestamp ioctl with an invalid
timestamp for a context then set a flag indicating that the ioctl
was called with an invalid ts. If the flag is set then do not
print error message about this ioctl being called with an invalid
timestamp. This is required to prevent the kernel log from
spamming with error messages and causing a watchdog.

CRs-fixed: 374586

Change-Id: Iffa5c13d74ed90b78f88aba5c4c0e0f908eeaa19
Signed-off-by: Shubhraprakash Das <sadas@codeaurora.org>
Signed-off-by: Rajeev Kulkarni <krajeev@codeaurora.org>