Revert "arm64: Remove unused macros from assembler.h"

This reverts commit <d3127afa>
("arm64: Remove unused macros from assembler.h")
This is required for flush_cache_all to work.

Change-Id: I469602e2f35b15bf13667322f3ffbe61dab90f91
Signed-off-by: Kyle Yan <kyan@codeaurora.org>
Signed-off-by: Channagoud Kadabi <ckadabi@codeaurora.org>
Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org>