msm: kgsl: Add CP_WAIT_FOR_IDLE packet before updating timestamp

HW workaround to resolve MMU pagefault caused by memory
freeing early before GPU completes it.

This is race condition where timestamp is getting updated
and the event handler runs before the GPU actually got done
with the timestamp, hence freeing the buffer early while GPU
still not completed with it.

Change-Id: I6d338d7dca680f57f2c39ed5a14381b261bf8bce
Signed-off-by: Anshuman Dani <adani@codeaurora.org>
(cherry picked from commit faf69cfeeede0883b9556e532d720ab4dc95b01d)

Signed-off-by: Sridhar Gujje <sgujje@codeaurora.org>
msm: kgsl: Properly record the size of the sglist in the memdesc

It was possible to fail out of kgsl_sharedmem_alloc after a sglist was
allocated but before we saved the size of the allocation which caused
problems when the sglist was freed during cleanup.

CRs-fixed: 464289
Change-Id: Ic0dedbadd57ec4d9422b5e3a873243d0ffed51f7
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>