arch: remove unused *_segments() macros/functions

Some architectures define the no-op macros/functions copy_segments,
release_segments and forget_segments. These are used nowhere in the
tree, so removed them.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Acked-by: Vineet Gupta <vgupta@synopsys.com>   [for arch/arc]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>