[POWERPC] Remove ibm4{xx,4x}.h from arch/powerpc

ARCH=powerpc should not use the ghastly un-multiplatformable tangle of
includes that starts with asm-ppc/ibm4xx.h.  This patch removes a
compile-breaking include of it from head_44x.S.
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/kernel/head_44x.S

@@ -32,8 +32,6 @@
 #include <asm/page.h>
 #include <asm/mmu.h>
 #include <asm/pgtable.h>
-#include <asm/ibm4xx.h>
-#include <asm/ibm44x.h>
 #include <asm/cputable.h>
 #include <asm/thread_info.h>
 #include <asm/ppc_asm.h>