RISC-V: Fix error code returned by riscv_hartid_to_cpuid()

We should return a negative error code upon failure in
riscv_hartid_to_cpuid() instead of NR_CPUS. This is also
aligned with all uses of riscv_hartid_to_cpuid() which
expect negative error code upon failure.

Fixes: 6825c7a80f ("RISC-V: Add logical CPU indexing for RISC-V")
Fixes: f99fb607fb ("RISC-V: Use Linux logical CPU number instead of hartid")
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

arch/riscv/kernel/smp.c

@@ -56,7 +56,7 @@ int riscv_hartid_to_cpuid(int hartid)
 			return i;
 
 	pr_err("Couldn't find cpu id for hartid [%d]\n", hartid);
-	return i;
+	return -ENOENT;
 }
 
 void riscv_cpuid_to_hartid_mask(const struct cpumask *in, struct cpumask *out)