powerpc/xmon: Remove empty xmon_map_scc()

This has been empty since 2005, commit 51d3082 "Unify udbg (#2)".

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/xmon/nonstdio.h

@@ -8,6 +8,5 @@ extern int xmon_getchar(void);
 extern void xmon_puts(const char *);
 extern char *xmon_gets(char *, int);
 extern void xmon_printf(const char *, ...);
-extern void xmon_map_scc(void);
 extern int xmon_write(const void *ptr, int nb);
 extern int xmon_readchar(void);