arm64: drop linker script hack to hide __efistub_ symbols

commit dd6846d774693bfa27d7db4dae5ea67dfe373fa1 upstream.

Commit 1212f7a16af4 ("scripts/kallsyms: filter arm64's __efistub_
symbols") updated the kallsyms code to filter out symbols with
the __efistub_ prefix explicitly, so we no longer require the
hack in our linker script to emit them as absolute symbols.

Cc: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
[ND: adjusted for context]
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>