Revert "arm64/alternatives: use subsections for replacement sequences"

This reverts commit d6d91458 which is
commit f7b93d42945cc71e1346dd5ae07c59061d56745e upstream as it makes
clang go boom in the build systems :(

Cc: Will Deacon <willdeacon@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I082c05e3d9cc00fd7173897a7c89c56aecf7facb