[POWERPC] fix showing xmon help

In some configuration, xmon help string is larger than xmon_printf
buffer. We need not to use printf. This patch adds xmon_puts and
change to use it to show help string.

Signed-off-by: Kou Ishizaki <[e-mail]>
Signed-off-by: Paul Mackerras <[e-mail]>

arch/powerpc/xmon/nonstdio.c

···
 	va_end(args);
 	xmon_write(xmon_outbuf, n);
 }
+
+void xmon_puts(const char *str)
+{
+	xmon_write(str, strlen(str));
+}

arch/powerpc/xmon/nonstdio.h

···
 
 extern int xmon_putchar(int c);
 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);

arch/powerpc/xmon/xmon.c

···
 			mdelay(2000);
 			return cmd;
 		case '?':
-			printf(help_string);
+			xmon_puts(help_string);
 			break;
 		case 'b':
 			bpt_cmds();