zynqmp: add missing Python package build dependencies

Currently one has to patch the PetaLinux installation to add these
missing dependencies. However, there should be no need to touch the
installation, which is often not feasible in e.g. corporate environments
anyway. Different OP-TEE releases require different dependencies; this
patch has been tested for all releases down to 3.5.0.

Signed-off-by: Stefan Wiehler <stefan.wiehler@missinglinkelectronics.com>
Reviewed-by: Joakim Bech <joakim.bech@linaro.org>