Address another warnings reported by Patrick Laimbock when compiling
in userspace. While there, improve consistency.

MFC after: 1 week
Address warnings generated by the clang analyzer.

MFC after: 1 week
Generalise the va to pa code and use it when starting secondary cores

Reviewed by:	ian@, rpaulo@
Differential Revision: https://reviews.freebsd.org/D736
Remove Lvirtaddr and Lphysaddr, these don't appear to be used.
Remove redundant kern conf entries that are inherited via include

Move cfg to spi1 as that's where it is located from the factory
When entering the kernel with the MMU off assume we are running from a
va == pa map.

I'm not sure the code would work if we are not running from the identity
map as the ARM core may attempt to read the next instruction from an
invalid memory location.