Add MIRRORED_REPEAT.

Change-Id: I08c73f684b5b4c2ac350bc3da7a505ce89d16035
diff --git a/rsDefines.h b/rsDefines.h
index dfa0f9d..b00cecc 100644
--- a/rsDefines.h
+++ b/rsDefines.h
@@ -194,6 +194,7 @@
     RS_SAMPLER_WRAP,
     RS_SAMPLER_CLAMP,
     RS_SAMPLER_LINEAR_MIP_NEAREST,
+    RS_SAMPLER_MIRRORED_REPEAT,
 
     RS_SAMPLER_INVALID = 100,
 };