Using procd allows better control and monitoring of the bmx7 process.
Keep polling for mac80211.sh process for now until we find a better
way to make sure that wireless configuration has been generated before
starting bmx7.
Setting maximum core size to 20000 looks dangerous on small devices,
but keep it as it was before, we shall discuss this separately.
Signed-off-by: Daniel Golle <daniel@makrotopia.org>