Re-work efidev ordering to fix efirt preloaded by loader on amd64

On amd64, efi_enter calls fpu_kern_enter(). This may not be called until
fpuinitstate has been invoked, resulting in a kernel panic with
efirt_load="YES" in loader.conf(5).

Move fpuinitstate a little earlier in SI_SUB_DRIVERS so that we can squeeze
efirt between it and efirtc at SI_SUB_DRIVERS, SI_ORDER_ANY. efidev must be
after efirt and doesn't really need to be at SI_SUB_DEVFS, so drop it at
SI_SUB_DRIVER, SI_ORDER_ANY.

The not immediately obvious dependency of fpuinitstate by efirt has been
noted in both places.

Discussed with: kib, andrew
Reported by: Jakob Alvermark <jakob@alvermark.net>
X-MFC-With: r330868