omxil: Use a fake library name when loading IOMX

The iomx loading stub doesn't use the library name.
If there's errors in loading the function pointers, this
gives slightly more correct error messages.
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/codec/omxil/omxil.c

@@ -58,9 +58,13 @@
  *****************************************************************************/
 static const char *ppsz_dll_list[] =
 {
+#if defined(USE_IOMX)
+    "libiomx.so", /* Not used when using IOMX, the lib should already be loaded */
+#else
     "libOMX_Core.so", /* TI OMAP IL core */
     "libOmxCore.so", /* Qualcomm IL core */
     "libomxil-bellagio.so",  /* Bellagio IL core */
+#endif
     0
 };