Remove old definition of "reverse" from stdlib_noniso

Fixes: #5045

Author: me-no-dev

Diff for: cores/esp32/stdlib_noniso.c

@@ -29,18 +29,6 @@
 #include <math.h>
 #include "stdlib_noniso.h"
 
-void reverse(char* begin, char* end) {
-    char *is = begin;
-    char *ie = end - 1;
-    while(is < ie) {
-        char tmp = *ie;
-        *ie = *is;
-        *is = tmp;
-        ++is;
-        --ie;
-    }
-}
-
 char* ltoa(long value, char* result, int base) {
     if(base < 2 || base > 16) {
         *result = 0;