MIPS: Support extended ASIDs

Add support for extended ASIDs as determined by the Config4.AE bit.
Since the only supported CPUs known to implement this are Netlogic XLP
and MIPS I6400, select this variable ASID support based upon
CONFIG_CPU_XLP and CONFIG_CPU_MIPSR6.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Jayachandran C. <jchandra@broadcom.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13211/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>