This fixes an error when building musl powerpc{32,64} with clang
(it doesn't know GNU as ignores .end arguments):

../src/ldso/powerpc/dlsym.s:8:10: error: unexpected token in '.end' directive
          .end    dlsym

I'm not sure if  .size   dlsym, .-dlsym should also be deleted to be
consistent with other archs.