DRI2: Rely less on the information from DRI2BufferRec

When moving further to our own DRI2 buffers bookkeeping, we can't
really trust the information from DRI2BufferRec anymore. So just add
a copy of all the missing bits of information to UMPBufferInfoRec
and use it instead.

Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>