svga: Add render_condition boolean flag in struct svga_context

svga: Add render_condition boolean flag in struct svga_context

set render_condition flag when driver performs conditional rendering.
Blit using DXPredCopyRegion command gets affected by conditional rendering so
We should check this flag while performing blit operation

Tested with piglit tests.

v2: As per Charmaine's comment, setting render_condition flag if svga_query is valid.
Tested with pigit tests.

Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Charmaine Lee <charmainel@vmware.com>