[all] Overflow when PPM frame length was at maximum with a 4-CH output

src/pulses_arm.cpp

@@ -135,6 +135,7 @@ void setupPulsesPPM(PPM_PORT_PARAM)                   // Don't enable interrupts
     rest -= v;
     *ptr++ = v; /* as Pat MacKenzie suggests */
   }
+  rest = (rest > 65535) ? 65535 : rest;
   *ptr = rest;
   *(ptr + 1) = 0;
 

src/pulses_avr.cpp

@@ -176,6 +176,7 @@ void setupPulsesPPM(uint8_t proto)
     }
 
     *ptr++ = q;  
+    rest = (rest > 65535) ? 65535 : rest;
     *ptr++ = rest;
 
     if (proto == PROTO_PPM) {