perf tools: Drop strxfrchar(), use strreplace() equivalent from kernel

No change in behaviour intended, just reducing the codebase and using
something available in tools/lib/.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-oyi6zif3810nwi4uu85odnhv@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/string2.h

@@ -21,7 +21,6 @@ static inline bool strisglob(const char *str)
 	return strpbrk(str, "*?[") != NULL;
 }
 int strtailcmp(const char *s1, const char *s2);
-char *strxfrchar(char *s, char from, char to);
 
 char *asprintf_expr_inout_ints(const char *var, bool in, size_t nints, int *ints);