powerpc: Merge enough to start building in arch/powerpc.

This creates the directory structure under arch/powerpc and a bunch
of Kconfig files.  It does a first-cut merge of arch/powerpc/mm,
arch/powerpc/lib and arch/powerpc/platforms/powermac.  This is enough
to build a 32-bit powermac kernel with ARCH=powerpc.

For now we are getting some unmerged files from arch/ppc/kernel and
arch/ppc/syslib, or arch/ppc64/kernel.  This makes some minor changes
to files in those directories and files outside arch/powerpc.

The boot directory is still not merged.  That's going to be interesting.

Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/lib/copypage.S b/arch/powerpc/lib/copypage.S
new file mode 100644
index 0000000..733d616
--- /dev/null
+++ b/arch/powerpc/lib/copypage.S
@@ -0,0 +1,121 @@
+/*
+ * arch/ppc64/lib/copypage.S
+ *
+ * Copyright (C) 2002 Paul Mackerras, IBM Corp.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+#include <asm/processor.h>
+#include <asm/ppc_asm.h>
+
+_GLOBAL(copy_page)
+	std	r31,-8(1)
+	std	r30,-16(1)
+	std	r29,-24(1)
+	std	r28,-32(1)
+	std	r27,-40(1)
+	std	r26,-48(1)
+	std	r25,-56(1)
+	std	r24,-64(1)
+	std	r23,-72(1)
+	std	r22,-80(1)
+	std	r21,-88(1)
+	std	r20,-96(1)
+	li	r5,4096/32 - 1
+	addi	r3,r3,-8
+	li	r12,5
+0:	addi	r5,r5,-24
+	mtctr	r12
+	ld	r22,640(4)
+	ld	r21,512(4)
+	ld	r20,384(4)
+	ld	r11,256(4)
+	ld	r9,128(4)
+	ld	r7,0(4)
+	ld	r25,648(4)
+	ld	r24,520(4)
+	ld	r23,392(4)
+	ld	r10,264(4)
+	ld	r8,136(4)
+	ldu	r6,8(4)
+	cmpwi	r5,24
+1:	std	r22,648(3)
+	std	r21,520(3)
+	std	r20,392(3)
+	std	r11,264(3)
+	std	r9,136(3)
+	std	r7,8(3)
+	ld	r28,648(4)
+	ld	r27,520(4)
+	ld	r26,392(4)
+	ld	r31,264(4)
+	ld	r30,136(4)
+	ld	r29,8(4)
+	std	r25,656(3)
+	std	r24,528(3)
+	std	r23,400(3)
+	std	r10,272(3)
+	std	r8,144(3)
+	std	r6,16(3)
+	ld	r22,656(4)
+	ld	r21,528(4)
+	ld	r20,400(4)
+	ld	r11,272(4)
+	ld	r9,144(4)
+	ld	r7,16(4)
+	std	r28,664(3)
+	std	r27,536(3)
+	std	r26,408(3)
+	std	r31,280(3)
+	std	r30,152(3)
+	stdu	r29,24(3)
+	ld	r25,664(4)
+	ld	r24,536(4)
+	ld	r23,408(4)
+	ld	r10,280(4)
+	ld	r8,152(4)
+	ldu	r6,24(4)
+	bdnz	1b
+	std	r22,648(3)
+	std	r21,520(3)
+	std	r20,392(3)
+	std	r11,264(3)
+	std	r9,136(3)
+	std	r7,8(3)
+	addi	r4,r4,640
+	addi	r3,r3,648
+	bge	0b
+	mtctr	r5
+	ld	r7,0(4)
+	ld	r8,8(4)
+	ldu	r9,16(4)
+3:	ld	r10,8(4)
+	std	r7,8(3)
+	ld	r7,16(4)
+	std	r8,16(3)
+	ld	r8,24(4)
+	std	r9,24(3)
+	ldu	r9,32(4)
+	stdu	r10,32(3)
+	bdnz	3b
+4:	ld	r10,8(4)
+	std	r7,8(3)
+	std	r8,16(3)
+	std	r9,24(3)
+	std	r10,32(3)
+9:	ld	r20,-96(1)
+	ld	r21,-88(1)
+	ld	r22,-80(1)
+	ld	r23,-72(1)
+	ld	r24,-64(1)
+	ld	r25,-56(1)
+	ld	r26,-48(1)
+	ld	r27,-40(1)
+	ld	r28,-32(1)
+	ld	r29,-24(1)
+	ld	r30,-16(1)
+	ld	r31,-8(1)
+	blr