ACPI: replace strlen("string") with sizeof("string") -1

...both give the number of chars in the string
without the '\0', as strncmp() wants,
but sizeof() is compile-time.
Reported-by: NAlan Stern <stern@rowland.harvard.edu>
Cc: Pavel Vasilyev <pavel@pavlinux.ru>
Signed-off-by: NLen Brown <len.brown@intel.com>

drivers/acpi/sysfs.c

@@ -173,7 +173,7 @@ static int param_set_trace_state(const char *val, struct kernel_param *kp)
 {
 	int result = 0;
 
-	if (!strncmp(val, "enable", strlen("enable"))) {
+	if (!strncmp(val, "enable", sizeof("enable") - 1)) {
 		result = acpi_debug_trace(trace_method_name, trace_debug_level,
 					  trace_debug_layer, 0);
 		if (result)
@@ -181,7 +181,7 @@ static int param_set_trace_state(const char *val, struct kernel_param *kp)
 		goto exit;
 	}
 
-	if (!strncmp(val, "disable", strlen("disable"))) {
+	if (!strncmp(val, "disable", sizeof("disable") - 1)) {
 		int name = 0;
 		result = acpi_debug_trace((char *)&name, trace_debug_level,
 					  trace_debug_layer, 0);