Revert "powerpc/build: vdso linker warning for orphan sections"

This reverts commit f2af2010.

It added a usage of cc-ldoption, but cc-ldoption was removed in commit
055efab3 ("kbuild: drop support for cc-ldoption").

Reported-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>