arm64: introduce binfmt_elf32.c

maillist inclusion
category: feature
bugzilla: 46790
CVE: NA

Reference: https://github.com/norov/linux/commits/ilp32-5.2



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As we support more than one compat formats, it looks more reasonable
to not use fs/compat_binfmt.c. Custom binfmt_elf32.c allows to move aarch32
specific definitions there and make code more maintainable and readable.

Signed-off-by: Yury Norov <ynorov@caviumnetworks.com>
Signed-off-by: Yury Norov <ynorov@marvell.com>

 Conflicts:
	arch/arm64/include/asm/elf.h
	arch/arm64/kernel/Makefile

Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Chen Jun <chenjun102@huawei.com>