AArch64: Revert setting of elf class in linker stub.

AArch64: Revert setting of elf class in linker stub.

This changes the fix to PR 25210 by removing the ELF class change.
As it turns out the correct change was only the change in compress.c.

Everything else is unneeded and setting the elf class is making the linker
behave very oddly under LTO.  The first stub is correctly written out but for
the rest the suddenly don't have a pointer to the stub section anymore.

This caused SPEC to fail as the program would branch to the stub and it wouldn't
be filled in.

Committed to master under the trivial rule as this is partially reverting a previous commit.

bfd/ChangeLog:

	PR 25210
	* elfnn-aarch64.c (_bfd_aarch64_create_stub_section): Remove elfclass.