Add support for i.MX6 VPU

jni/nv_imx_dec/nv_imx_dec.h

@@ -0,0 +1,7 @@
+#include <jni.h>
+
+int nv_imx_init(void);
+
+int nv_imx_decode(unsigned char* indata, int inlen, int last);
+
+void nv_imx_destroy(void);