FIX: Coverity Scan warnings on not using the fread return value.

client/cmdlfhitag.c

@@ -173,7 +173,8 @@ int CmdLFHitagSim(const char *Cmd) {
 			return 1;
 		}
 		tag_mem_supplied = true;
-		if (fread(c.d.asBytes,48,1,pf) == 0) {
+		size_t bytes_read = fread(c.d.asBytes, 48, 1, pf);
+		if ( bytes_read == 0) {
 			PrintAndLog("Error: File reading error");
 			fclose(pf);
 			return 1;