KVM: MIPS: Make kvm_mips_callbacks const

Make kvm_mips_callbacks fully const as it's now hardcoded to point at
kvm_vz_callbacks, the only remaining the set of callbacks.

Link: https://lore.kernel.org/all/beb697c2-dfad-780e-4638-76b229f28731@linaro.org
Suggested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Link: https://lore.kernel.org/r/20230224192832.1286267-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: sean-jc

arch/mips/include/asm/kvm_host.h

@@ -757,7 +757,7 @@ struct kvm_mips_callbacks {
 	int (*vcpu_run)(struct kvm_vcpu *vcpu);
 	void (*vcpu_reenter)(struct kvm_vcpu *vcpu);
 };
-extern struct kvm_mips_callbacks *kvm_mips_callbacks;
+extern const struct kvm_mips_callbacks * const kvm_mips_callbacks;
 int kvm_mips_emulation_init(void);
 
 /* Debug: dump vcpu state */

arch/mips/kvm/vz.c

@@ -3305,7 +3305,7 @@ static struct kvm_mips_callbacks kvm_vz_callbacks = {
 };
 
 /* FIXME: Get rid of the callbacks now that trap-and-emulate is gone. */
-struct kvm_mips_callbacks *kvm_mips_callbacks = &kvm_vz_callbacks;
+const struct kvm_mips_callbacks * const kvm_mips_callbacks = &kvm_vz_callbacks;
 
 int kvm_mips_emulation_init(void)
 {