unicore32 core architecture: generic elf and ksyms stuff

This patch includes some generic stuff including elf and ksyms.
Because all one-line asm-generic headers are auto-generated by ASM_GENERIC_HEADERS
in arch/unicore32/Makefile, so the rest seems very little.
ELF handling functions and module handling functions are also here.

Signed-off-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>