[PATCH] powerpc: Kill _machine and hard-coded platform numbers

This removes statically assigned platform numbers and reworks the
powerpc platform probe code to use a better mechanism.  With this,
board support files can simply declare a new machine type with a
macro, and implement a probe() function that uses the flattened
device-tree to detect if they apply for a given machine.

We now have a machine_is() macro that replaces the comparisons of
_machine with the various PLATFORM_* constants.  This commit also
changes various drivers to use the new macro instead of looking at
_machine.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/drivers/ide/pci/via82cxxx.c b/drivers/ide/pci/via82cxxx.c
index c85b87c..3e677c4 100644
--- a/drivers/ide/pci/via82cxxx.c
+++ b/drivers/ide/pci/via82cxxx.c
@@ -440,7 +440,7 @@
 
 
 #if defined(CONFIG_PPC_CHRP) && defined(CONFIG_PPC32)
-	if(_machine == _MACH_chrp && _chrp_type == _CHRP_Pegasos) {
+	if(machine_is(chrp) && _chrp_type == _CHRP_Pegasos) {
 		hwif->irq = hwif->channel ? 15 : 14;
 	}
 #endif