rtos: Unbreak semaphore, trade assert for saturation with original limit

Before rtx 5, the max count on semaphores was UINT16_MAX, aftewards it
was decreased to 1024 with an assert on overflow.

This is especially problematic for semaphores used for signaling, since
there is no replacement currently available in C++.

platform/mbed_retarget.cpp

@@ -1014,6 +1014,11 @@ extern "C" void EvrRtxMutexError (osMutexId_t mutex_id, int32_t status)
 
 extern "C" void EvrRtxSemaphoreError (osSemaphoreId_t semaphore_id, int32_t status)
 {
+    // Ignore semaphore overflow, the count will saturate with a returned error
+    if (status == osRtxErrorSemaphoreCountLimit) {
+        return;
+    }
+
     error("Semaphore %p error %i\r\n", semaphore_id, status);
 }
 

rtos/Semaphore.cpp

@@ -27,7 +27,7 @@
 namespace rtos {
 
 Semaphore::Semaphore(int32_t count) {
-    constructor(count, 1024);
+    constructor(count, 0xffff);
 }
 
 Semaphore::Semaphore(int32_t count, uint16_t max_count) {