Read the arm64 midr register earlier

We use the midr_el1 register to decode which CPU type we are booting
from. Read it on the secondary CPUs before waiting for the boot CPU
to release us as it will need to use it before the release.

Sponsored by: The FreeBSD Foundation

(cherry picked from commit 6b22840ed0e8f9ceb34465987b8469a43ebb4582)