Move setting of console earlier in boot.

There's no reason we can't setup the console first thing after the
arch flags are setup. We set it undconditionally to efi. This is a
good default, and will get us error messages to at least the efi
console no matter what. This will also prime the pump so that as other
variables are set, they will take effect and the console will be
correct as soon as those env vars are set. Also remove the redundant
setting of the console to efi when we know the console is efi.

Differential Revision: https://reviews.freebsd.org/D20014