ppc/arm: zap EMK boards

The following bard configurations have been without active maintenance
for a long time, and the board maintainer agrees to have them removed:

MPC5200:	TOP5200, MINI5200, EVAL5200
MPC860:		TOP860
at91sam9xeXXX:	top9000eval_xe, top9000su_xe

Signed-off-by: Wolfgang Denk <wd@denx.de>
Cc: Reinhard Meyer <reinhard.meyer@emk-elektronik.de>
[trini: Add missing Kconfig removals]
Signed-off-by: Tom Rini <trini@ti.com>