Get rid of mixed tabs and spaces in the aarch64 assembly
Unify the indentation of the new aarch64 assembly
Unify the copyright header in the aarch64 deblocking assembly

This file was the only one that had a differently formatted
copyright header.
Fix building the deblocking aarch64 assembly with gnu binutils
Merge pull request #975 from mstorsjo/cleanup-asm

Clean up the aarch64 deblocking assembly