[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/cirrusfb.c b/drivers/video/cirrusfb.c
index 66d6f2f..1103010 100644
--- a/drivers/video/cirrusfb.c
+++ b/drivers/video/cirrusfb.c
@@ -60,8 +60,8 @@
 #include <asm/amigahw.h>
 #endif
 #ifdef CONFIG_PPC_PREP
-#include <asm/processor.h>
-#define isPReP (_machine == _MACH_prep)
+#include <asm/machdep.h>
+#define isPReP (machine_is(prep))
 #else
 #define isPReP 0
 #endif