Schwabe/silence register warnings clang (#3940)

* Ignore deprecated register warning for the the STM include files

Ignore the warning with the use of #pragma which is not elegant but otherwise we would have to change the vendor files

* Remove usage of register in C/C++ files.

Modern compilers ignore it anyway and C++11 actually deprecates it. Removing also removes a number of clang warnings about this

radio/src/targets/sky9x/haptic_driver.cpp

@@ -30,7 +30,7 @@ void hapticOff()
 // pwmPercent 0-100
 void hapticOn( uint32_t pwmPercent )
 {
-  register Pwm *pwmptr ;
+  Pwm *pwmptr ;
 
   pwmptr = PWM ;