added help for arguments in case user doesn't give any arguments (#138)

[ROCm/rocdecode commit: 5930f15c1a]

projects/rocdecode/samples/videoDecodeRGB/videodecrgb.cpp

@@ -166,7 +166,7 @@ int main(int argc, char **argv) {
     int rgb_width;
 
     // Parse command-line arguments
-    if(argc < 1) {
+    if(argc <= 1) {
         ShowHelpAndExit();
     }
     for (int i = 1; i < argc; i++) {