MIPS: only register MT SMP ops if MT is supported

Verify that the current CPU actually supports multi-threading before
registering MT SMP ops, instead of unconditionally registering them if
the kernel is compiled with CONFIG_MIPS_MT_SMP.

Suggested-by: Jiaxun Yang <[e-mail]>
Signed-off-by: Sander Vanheule <[e-mail]>
Signed-off-by: Thomas Bogendoerfer <[e-mail]>

arch/mips/include/asm/smp-ops.h

···
 #ifdef CONFIG_MIPS_MT_SMP
 	extern const struct plat_smp_ops vsmp_smp_ops;
 
+	if (!cpu_has_mipsmt)
+		return -ENODEV;
+
 	register_smp_ops(&vsmp_smp_ops);
 
 	return 0;