powerpc: convert to use __HEAD and HEAD_TEXT macros.

This has the consequence of changing the section name use for head
code from ".text.head" to ".head.text".  Since this commit changes all
users in the architecture, this change should be harmless.

Signed-off-by: Tim Abbott <tabbott@mit.edu>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/powerpc/kernel/head_8xx.S

@@ -19,6 +19,7 @@
  *
  */
 
+#include <linux/init.h>
 #include <asm/processor.h>
 #include <asm/page.h>
 #include <asm/mmu.h>
@@ -38,7 +39,7 @@
 #else
 #define DO_8xx_CPU6(val, reg)
 #endif
-	.section	.text.head, "ax"
+	__HEAD
 _ENTRY(_stext);
 _ENTRY(_start);