dont spam the console with qfull warnings. this makes things worse.
handle loopback packets as stated in the comment. we call etheriq()
with fromwire=1 for loopback packets so etheriq() can pass the packet
on (without copying) or free it. dont inhibit interrupts while calling
etheriq(). etheriq() can safely be called from process and interrupt
context. it is unclear what this was supposed to fix and testing didnt
seem to have any odd effects.
