kern/170864: [patch] Move SPI flash from AR71XX_BASE (kernel) to board specific files

>Number:         170864
>Category:       kern
>Synopsis:       [patch] Move SPI flash from AR71XX_BASE (kernel) to board specific files
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Wed Aug 22 13:00:27 UTC 2012
>Closed-Date:
>Last-Modified:
>Originator:     Luiz Otavio O Souza
>Release:        -current
>Organization:
>Environment:
FreeBSD rb450g 10.0-CURRENT FreeBSD 10.0-CURRENT #20 r238655:239327M: Thu Aug 16 20:09:08 BRT 2012    
root <at> server01:/data/rb/rb450g/obj/mips.mips/data/rb/rb450g/src/sys/RB4XX  mips

>Description:
Not all routers/boards models built on top of AR71XX uses a SPI flash as storage device, so move the 'device
mx25l' to board specific kernel files where it is used.

With this change we can use AR71XX_BASE based kernels with other kind of storages (like NAND).
>How-To-Repeat: