Pull up following revision(s) (requested by skrll in ticket #1238):

sys/arch/arm/cortex/gic.c: revision 1.47

Only target the boot cpu for real with SPI interrupts.  I tried to do
this back in 2014, but somehow I missed a spot.

This is a quick-and-dirty fix for the USB stack which expects transfer
completions to be in-order.  If interrupts happen across the CPUs then
this isn't guaranteed (yet).

kern/55243 panic at usb_transfer_complete() on raspberry pi 4

(martin)