cris: remove arch/cris/arch-v32/lib/nand_init.S

Commit 3f50c067 ("CRIS v32: Update
boot/rescue/head.S code") removed the last reference to that file. So
this file is unused since v2.6.25.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>