x86-asm-2021-06-28

 - Micro-optimize and standardize the do_syscall_64() calling convention
 - Make syscall entry flags clearing more conservative
 - Clean up syscall table handling
 - Clean up & standardize assembly macros, in preparation of FRED
 - Misc cleanups and fixes

Signed-off-by: Ingo Molnar <mingo@kernel.org>