gallium-intel: Link dri2 driver with softpipe

src/gallium/winsys/drm/intel/dri2/Makefile

@@ -6,6 +6,7 @@ LIBNAME = i915_dri.so
 PIPE_DRIVERS = \
 	$(TOP)/src/gallium/state_trackers/dri2/libdri2drm.a \
 	$(TOP)/src/gallium/winsys/drm/intel/gem/libinteldrm.a \
+	$(TOP)/src/gallium/drivers/softpipe/libsoftpipe.a \
 	$(TOP)/src/gallium/drivers/i915simple/libi915simple.a