i965,meta: Stop unlocking the texture to try and prevent deadlocks.

i965,meta: Stop unlocking the texture to try and prevent deadlocks.

Unlocking the texture is not safe: another thread could come in and grab
it.  Now that we use a recursive mutex, this should work.  This also fixes
texture lock deadlocks in the new meta fast clear path.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Kristian Høgsberg <krh@bitplanet.net>
Tested-by: Chris Forbes <chrisf@ijw.co.nz>