missing backports for x86 syscall function prototype cleanups

Hi!

Sami pointed out to me that 4 of 6 patches in Linus's tree that were cleaning up the x86 syscall function prototypes didn't make it into -stable.

These were backported:

8661d769ab77 ("syscalls/x86: Use the correct function type in SYSCALL_DEFINE0") (as e79138ba8e0ec84f3ab5daa4761e4d534bbc682d) f53e2cd0b8ab ("x86/mm: Use the correct function type for native_set_fixmap()") (as a823d762a57519adeb33f5f12f761d636e42d32e)

But these are missing, leading to some confusion when working with v5.4 under CFI:

cf3b83e19d7c928e05a5d193c375463182c6029a 00198a6eaf66609de5e4de9163bb42c7ca9dd7b7 f48f01a92cca09e86d46c91d8edf9d5a71c61727 6e4847640c6aebcaa2d9b3686cecc91b41f09269

Can these get added please?

Thanks!