KVM: MIPS: Remove duplicated ASIDs from vcpu

The kvm_vcpu_arch structure contains both mm_structs for allocating MMU
contexts (primarily the ASID) but it also copies the resulting ASIDs
into guest_{user,kernel}_asid[] arrays which are referenced from uasm
generated code.

This duplication doesn't seem to serve any purpose, and it gets in the
way of generalising the ASID handling across guest kernel/user modes, so
lets just extract the ASID straight out of the mm_struct on demand, and
in fact there are convenient cpu_context() and cpu_asid() macros for
doing so.

To reduce the verbosity of this code we do also add kern_mm and user_mm
local variables where the kernel and user mm_structs are used.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

arch/mips/include/asm/kvm_host.h

@@ -321,9 +321,7 @@ struct kvm_vcpu_arch {
 	/* S/W Based TLB for guest */
 	struct kvm_mips_tlb guest_tlb[KVM_MIPS_GUEST_TLB_SIZE];
 
-	/* Cached guest kernel/user ASIDs */
-	u32 guest_user_asid[NR_CPUS];
-	u32 guest_kernel_asid[NR_CPUS];
+	/* Guest kernel/user [partial] mm */
 	struct mm_struct guest_kernel_mm, guest_user_mm;
 
 	/* Guest ASID of last user mode execution */