x86/asm: Clean up copy_page_*() comments and code

Modern CPUs use fast-string instruction to accelerate copy
performance, by combining data into 128 bit chunks.

Modify comments and coding style to match it.

Signed-off-by: Ma Ling <ling.ma@intel.com>
Cc: iant@google.com
Link: http://lkml.kernel.org/r/1350503565-19167-1-git-send-email-ling.ma@intel.com


[ Cleaned up the clean up. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>