obs-qsv11: Fix double free on CreateSurface failure

_dx9_simple_free already frees this pointer. I don't think this code
path is currently reachable, but it should probably still be fixed.
Detected by Coverity Scan.

plugins/obs-qsv11/common_directx9.cpp

@@ -393,7 +393,6 @@ mfxStatus _dx9_simple_alloc(mfxFrameAllocRequest *request,
 			if (FAILED(hr)) {
 				_dx9_simple_free(response);
 				MSDK_SAFE_FREE(dxMids);
-				MSDK_SAFE_FREE(dxMidPtrs);
 				return MFX_ERR_MEMORY_ALLOC;
 			}
 			dxMidPtrs[i] = &dxMids[i];