[gem] Enable bo_reuse by default.

The objects are swappable, so we're less concerned by excessive object
allocation now, and it's about a 20% performance improvement.  If we get
concerns about the memory consumption from others, we can look into a
compromise position later.

src/mesa/drivers/dri/intel/intel_screen.c

@@ -59,7 +59,7 @@ PUBLIC const char __driConfigOptions[] =
       /* Options correspond to DRI_CONF_BO_REUSE_DISABLED,
        * DRI_CONF_BO_REUSE_ALL
        */
-      DRI_CONF_OPT_BEGIN_V(bo_reuse, enum, 0, "0:1")
+      DRI_CONF_OPT_BEGIN_V(bo_reuse, enum, 1, "0:1")
 	 DRI_CONF_DESC_BEGIN(en, "Buffer object reuse")
 	    DRI_CONF_ENUM(0, "Disable buffer object reuse")
 	    DRI_CONF_ENUM(1, "Enable reuse of all sizes of buffer objects")