amd: fix empty-body issues

Signed-off-by: Eric Engestrom <eric.engestrom@intel.com>
Fixes: 8d43e2b2 ("meson: add -Werror=empty-body to disallow `if(x);`")
Reviewed-By: Timur Kristóf <timur.kristof@gmail.com>
(cherry picked from commit 51569e52)