Null check before setting offset

[ROCm/clr commit: f17c897751]

projects/clr/hipamd/src/hip_texture.cpp

@@ -676,7 +676,8 @@ hipError_t hipGetTextureAlignmentOffset(size_t* offset, const textureReference*
 
     auto ctx = ihipGetTlsDefaultCtx();
     if (ctx) {
-        *offset = 0;
+        if(offset != nullptr)
+            *offset = 0;
     }
     return ihipLogStatus(hip_status);
 }