[PATCH] PPC64 call ibm,os-term only if its available

This patch is from Olaf Hering.

The rtas property 'ibm,os-term' is not available on JS20, a panic will print:

unable to mount root filesystem on /dev/hda
Kernel panic - not syncing: Attempted to kill init!
 <0>ibm,os-term call failed -1
Rebooting in 42 seconds..
Signed-off-by: Olaf Hering <olh@suse.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/ppc64/kernel/rtas.c

@@ -455,6 +455,9 @@ void rtas_os_term(char *str)
 {
 	int status;
 
+	if (RTAS_UNKNOWN_SERVICE == rtas_token("ibm,os-term"))
+		return;
+
 	snprintf(rtas_os_term_buf, 2048, "OS panic: %s", str);
 
 	do {