arm64: Raise again L3 table for early devmap

The initial raise in r336519 wasn't enough for using big resolution
(1920 x 1200 for example). Raise it again.

Reported by: bob prohaska <fbsd@www.zefox.net>
Tested by: bob prohaska <fbsd@www.zefox.net>
Approved by: re (gjb@)