sparc: fix build error on gr_ep2s60 board

sparc: fix build error on gr_ep2s60 board

Commit 92ac52082140 (net: Remove all references to CONFIG_ETHADDR
and friends) accidentally dropped #endif.  Since then, gr_ep2s60
could not build.

scripts/kconfig/conf --silentoldconfig Kconfig
  CHK     include/config.h
  GEN     include/autoconf.mk
In file included from include/config.h:5:0,
                 from ./include/common.h:18:
include/configs/gr_ep2s60.h:15:0: error: unterminated #ifndef
 #ifndef __CONFIG_H__
 ^
make[1]: *** [include/autoconf.mk] Error 1

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>