boards.cfg: fix a configuration error of ep8248 board again

boards.cfg: fix a configuration error of ep8248 board again

"make ep8248_config" fails with an error like this:

    $ make ep8248_config
    make: *** [ep8248_config] Error 1

Its cause is that there are two entries for "ep8248".

The first is around line 661 of boards.cfg. (as Active)
The second appears around line 1242. (as Orphan)

This bug was originally introduced by commit e7e90901
and I fixed it by commit 8ad5d45e.
(Refer to git-log of commit 8ad5d45e)

But this bug was re-introduced by commit 05d134b0 because
the custodian made a mistake when he resolved a merge conflict.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Albert ARIBAUD <albert.u.boot@aribaud.net>
Cc: Heiko Schocher <hs@denx.de>
Cc: Kim Phillips <kim.phillips@linaro.org>