MIPS: BCM63xx: Utilize asm/bmips-spaces.h

Since BCM63xx runs on BMIPS3300 which requires the use of a FIXADDR_TOP
to avoid collisions with the SBR, utilize asm/bmips-spaces.h which
defines FIXADDR_TOP for us now.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: blogic@openwrt.org
Cc: cernekee@chromium.org
Cc: jogo@openwrt.org
Patchwork: https://patchwork.linux-mips.org/patch/9969/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Move FIXADDR_TOP into spaces.h

Memory maps and addressing quirks are normally defined in <spaces.h>.
There are already three targets that need to override FIXADDR_TOP, and
others exist. This will be a cleaner approach than adding lots of
ifdefs in fixmap.h .

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Cc: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/1573/
Acked-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>