ppc: Remove CHRP, POWER3 and POWER4 support from arch/ppc

32-bit CHRP machines are now supported only in arch/powerpc, as are
all 64-bit PowerPC processors.  This means that we don't use
Open Firmware on any platform in arch/ppc any more.

This makes PReP support a single-platform option like every other
platform support option in arch/ppc now, thus CONFIG_PPC_MULTIPLATFORM
is gone from arch/ppc.  CONFIG_PPC_PREP is the option that selects
PReP support and is generally what has replaced
CONFIG_PPC_MULTIPLATFORM within arch/ppc.

_machine is all but dead now, being #defined to 0.

Updated Makefiles, comments and Kconfig options generally to reflect
these changes.

Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/ppc/boot/simple/mpc10x_memory.c

@@ -50,10 +50,10 @@ MPC10X_PCI_OP(read, dword, u32 *, in_le32, 0)
  * the system.  This assumes that the firmware has correctly set up the memory
  * controller registers.  On CONFIG_PPC_PREP, we know we are being called
  * under a PReP memory map. On all other machines, we assume we are under
- * a CHRP memory map.  Further, on CONFIG_PPC_MULTIPLATFORM we must rename
+ * a CHRP memory map.  Further, on CONFIG_PPC_PREP we must rename
  * this function.
  */
-#ifdef CONFIG_PPC_MULTIPLATFORM
+#ifdef CONFIG_PPC_PREP
 #define get_mem_size mpc10x_get_mem_size
 #endif
 unsigned long

arch/ppc/boot/simple/relocate.S

@@ -194,7 +194,7 @@ start_ldr:
 	/*
 	 * Start at the begining.
 	 */
-#ifdef CONFIG_PPC_MULTIPLATFORM
+#ifdef CONFIG_PPC_PREP
 	li	r9,0xc
 	mtlr	r9
 	/* tell kernel we're prep, by putting 0xdeadc0de at KERNELLOAD,