In preparation for 32-bit MIPS huge page support.

EVA,XPA are extended-addressing modes for 32-bit MIPS systems. Because
huge pages aren't currently supported in 32-bit MIPS, this doesn't take
any features away from EVA,XPA-enabled systems. However, the soon-to-
come 32-bit MIPS huge page support doesn't yet support them.

This also disables CPU_SUPPORTS_HUGEPAGES for the small number of 32-bit
MIPS CPUs from Alchemy/Netlogic that support a custom 36-bit extended
addressing. It's unknown if they even support huge pages in hardware.
Signed-off-by: Daniel Silsby <dansilsby@gmail.com>
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: od@zcrc.me
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org