platform: mips: cpu_hwmon: Disable driver on unsupported hardware

cpu_hwmon is unsupported on CPUs without loongson_chiptemp
register and csr.

Cc: stable@vger.kernel.org
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

drivers/platform/mips/cpu_hwmon.c

@@ -139,6 +139,9 @@ static int __init loongson_hwmon_init(void)
 		csr_temp_enable = csr_readl(LOONGSON_CSR_FEATURES) &
 				  LOONGSON_CSRF_TEMP;
 
+	if (!csr_temp_enable && !loongson_chiptemp[0])
+		return -ENODEV;
+
 	nr_packages = loongson_sysconf.nr_cpus /
 		loongson_sysconf.cores_per_package;