[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>

drivers/net/tulip/de4x5.c

@@ -4160,7 +4160,7 @@ get_hw_addr(struct net_device *dev)
     ** If the address starts with 00 a0, we have to bit-reverse
     ** each byte of the address.
     */
-    if ( (_machine & _MACH_Pmac) &&
+    if ( machine_is(powermac) &&
 	 (dev->dev_addr[0] == 0) &&
 	 (dev->dev_addr[1] == 0xa0) )
     {