UAPI: Place comments in empty arch Kbuilds to make them non-empty

Place comments in:

arch/mips/include/asm/Kbuild
arch/tile/include/arch/Kbuild

to make them non-empty so that the patch program doesn't remove them when it
reduces them to nothing.

Possibly they should be just deleted, but it's possible that they'll acquire
generic-y or genhdr-y lines in future, so I'm keeping them around for the
moment.

Note that MIPS will compile happily if the file is deleted instead. I haven't
tested TILE, but I suspect it will be the same there.

Signed-off-by: David Howells <[e-mail]>
cc: Ralf Baechle <[e-mail]>
cc: Chris Metcalf <[e-mail]>

arch/mips/include/asm/Kbuild

···
+# MIPS headers

arch/tile/include/arch/Kbuild

···
+# Tile arch headers