[PATCH] powerpc: merge code values for identifying platforms

This patch merges platform codes.  systemcfg->platform is no longer used,
systemcfg use in general is deprecated as much as possible (and renamed
_systemcfg before it gets completely moved elsewhere in a future patch),
_machine is now used on ppc64 along as ppc32.  Platform codes aren't gone
yet but we are getting a step closer. A bunch of asm code in head[_64].S
is also turned into C code.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/kernel/traps.c

@@ -129,7 +129,7 @@ int die(const char *str, struct pt_regs *regs, long err)
 	nl = 1;
 #endif
 #ifdef CONFIG_PPC64
-	switch (systemcfg->platform) {
+	switch (_machine) {
 	case PLATFORM_PSERIES:
 		printk("PSERIES ");
 		nl = 1;