meta-phytec

tools: phytec-setup-release: modify script to pass default parameters

If user does not pass a machine or any arguments, use the following defaults:
machine configuration = "imx7-phyboard-zeta"
build dir name = "build"
graphical backend = "x11"

Signed-off-by: Anna Horstmann <ahorstmann@phytec.com>
(cherry picked from commit 688cdd7e8fda2daf5e324e28709cb91181faf3aa)