[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/video/nvidia/nvidia.c b/drivers/video/nvidia/nvidia.c
index a7c4e5e..7258b32 100644
--- a/drivers/video/nvidia/nvidia.c
+++ b/drivers/video/nvidia/nvidia.c
@@ -29,6 +29,7 @@
 #include <asm/pci-bridge.h>
 #endif
 #ifdef CONFIG_PMAC_BACKLIGHT
+#include <asm/machdep.h>
 #include <asm/backlight.h>
 #endif
 
@@ -1353,7 +1354,7 @@
 	NVWriteCrtc(par, 0x1a, vesa);
 
 #ifdef CONFIG_PMAC_BACKLIGHT
-	if (par->FlatPanel && _machine == _MACH_Pmac) {
+	if (par->FlatPanel && machine_is(powermac)) {
 		set_backlight_enable(!blank);
 	}
 #endif
@@ -1688,7 +1689,7 @@
 	       info->fix.id,
 	       par->FbMapSize / (1024 * 1024), info->fix.smem_start);
 #ifdef CONFIG_PMAC_BACKLIGHT
-	if (par->FlatPanel && _machine == _MACH_Pmac)
+	if (par->FlatPanel && machine_is(powermac))
 		register_backlight_controller(&nvidia_backlight_controller,
 					      par, "mnca");
 #endif