MIPS: BMIPS: Add BCM6358 support

MIPS: BMIPS: Add BCM6358 support

BCM6358 has a shared TLB which conflicts with current SMP support, so it must
be disabled for now.
BCM6358 uses >= 0xfffe0000 addresses for internal registers, which need to be
remapped (by using a simplified version of BRCM63xx ioremap.h).
However, 0xfff80000 is a better address, since it also covers BCM3368, leaving
the possibility to add it in the future.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Cc: f.fainelli@gmail.com
Cc: jogo@openwrt.org
Cc: cernekee@gmail.com
Cc: robh@kernel.org
Cc: simon@fire.lp0.eu
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: devicetree@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13040/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>