FROMLIST: BACKPORT: arm64: keep .altinstructions and .altinstr_replacement

Make sure the linker doesn't remove .altinstructions or
.altinstr_replacement when CONFIG_LD_DEAD_CODE_DATA_ELIMINATION is
enabled.

Bug: 62093296
Bug: 67506682
Change-Id: I73f8a96679083909ec6865ee87519163ac7dcbe3
(am from https://patchwork.kernel.org/patch/10085799/

)
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>