MT#60408 AmUriParser: Don't use register storage class

Don't store the `st` variable in a processor register
but store as usually in memory.

Resolves:

AmUriParser.cpp:97:16: warning: ISO C++17 does not allow 'register' storage class specifier [-Wregister]
   97 |   register int st = ST1;
      |

Change-Id: Ia38feab1e58aeab20e2f7319bee268feca919a82

core/AmUriParser.cpp

@@ -94,7 +94,7 @@ static inline int skip_uri(const string& s, unsigned int pos)
   unsigned int len = s.length() - pos;
   unsigned int p = pos;
 
-  register int st = ST1;
+  int st = ST1;
 
   while(len) {
     switch(s[p]) {