MFC 264219: Move sys/arm/econa to sys/arm/cavium/cns11xx.

Move sys/arm/econa to sys/arm/cavium/cns11xx.

Remove #include <machine/frame.h> from all the arm code that doesn't
really need it. That would be almost everywhere it was included. Add
it in a couple files that really do need it and were previously getting
it by accident via another header.

Add support for Cavium Econa CNS11XX ARM boards. These boards were
previously know by StarSemi STR9104.

Tested by the submitter on an Emprex NSD-100 board.

Submitted by: Yohanes Nugroho <yohanes at gmail.com>
Reviewed by: freebsd-arm, stas
Obtained from: //depot/projects/str91xx/...