The same definitions are used for the bounds logic and the asm-offsets.h
generation by kbuild. Put them into include/linux/kbuild.h file.

Also add a new feature

COMMENT("text")

which can be used to insert lines of ocmments into asm-offsets.h and
bounds.h.

Cc: Sam Ravnborg
Signed-off-by: Christoph Lameter
Cc: Ingo Molnar
Cc: Thomas Gleixner
Cc: Ralf Baechle
Cc: Jay Estabrook
Cc: Ivan Kokshaysky
Cc: Richard Henderson
Cc: "Luck, Tony"
Cc: Russell King
Cc: Chris Zankel
Cc: David S. Miller
Cc: Haavard Skinnemoen
Cc: Bryan Wu
Cc: Mike Frysinger
Cc: Yoshinori Sato
Cc: Geert Uytterhoeven
Cc: Roman Zippel
Cc: Greg Ungerer
Cc: David Howells
Cc: Kyle McMartin
Cc: Grant Grundler
Cc: Matthew Wilcox
Cc: Paul Mackerras
Cc: Benjamin Herrenschmidt
Cc: Martin Schwidefsky
Cc: Heiko Carstens
Cc: Paul Mundt
Cc: Miles Bader
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds