Various files are needlessly rebuilt every time due to the version and
build time changing. As version.h is not actually needed, remove the
include.

Signed-off-by: Rob Herring
Cc: Albert Aribaud
Cc: Stefano Babic
Cc: Minkyu Kang
Cc: Marek Vasut
Cc: Tom Warren
Cc: Michal Simek
Cc: Macpaul Lin
Cc: Wolfgang Denk
Cc: York Sun
Cc: Stefan Roese
Cc: Nobuhiro Iwamatsu
Cc: Simon Glass
Cc: Philippe Reynes
Cc: Eric Jarrige
Cc: "David Müller"
Cc: Phil Edworthy
Cc: Robert Baldyga
Cc: Torsten Koschorrek
Cc: Anatolij Gustschin
Reviewed-by: Linus Walleij
Reviewed-by: Łukasz Majewski