arm64: ELF: add support for big-endian executables

This patch adds support for the aarch64_be ELF format to the AArch64 ELF
loader.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Git-commit: 5436b5c8305b4ed37c5d11f96c1aaccca63c9ab2
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Ian Maund <imaund@codeaurora.org>