linux-user: Move get_vdso_image_info to arm/elfload.c Rename from vdso_image_info to avoid a symbol clash. Define HAVE_VDSO_IMAGE_INFO to signal the external definition exists. Provide fallback versions for other targets. Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>