Unify our assembler macros.

Our <machine/asm.h> files were modified from upstream, to the extent
that no architecture was actually using the upstream ENTRY or END macros,
assuming that architecture even had such a macro upstream. This patch moves
everyone to the same macros, with just a few tweaks remaining in the
<machine/asm.h> files, which no one should now use directly.

I've removed most of the unused cruft from the <machine/asm.h> files, though
there's still rather a lot in the mips/mips64 ones.

Bug: 12229603
Change-Id: I2fff287dc571ac1087abe9070362fb9420d85d6d
diff --git a/libc/arch-mips/string/memcpy.S b/libc/arch-mips/string/memcpy.S
index aabdfcf..dc91096 100644
--- a/libc/arch-mips/string/memcpy.S
+++ b/libc/arch-mips/string/memcpy.S
@@ -39,13 +39,13 @@
  *  Include files
  ************************************************************************/
 
-#include "machine/asm.h"
+#include <private/bionic_asm.h>
 
 
-/* 
+/*
  * This routine could be optimized for MIPS64. The current code only
  * uses MIPS32 instructions.
- */	
+ */
 #if defined(__MIPSEB__)
 #  define LWHI	lwl		/* high part is left in big-endian	*/
 #  define SWHI	swl		/* high part is left in big-endian	*/