tools: cpupower: fix wrong err msg not supported vs not available

idlestates in sysfs are counted from 0.

This fixes a wrong error message.
Current behavior on a machine with 4 sleep states is:

cpupower idle-set -e 4
Idlestate 4 enabled on CPU 0

-----Wrong---------------------
cpupower idle-set -e 5
Idlestate enabling not supported by kernel
-----Must and now will be -----
cpupower idle-set -e 5
Idlestate 6 not available on CPU 0
-------------------------------

cpupower idle-set -e 6
Idlestate 6 not available on CPU 0
Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

tools/power/cpupower/utils/helpers/sysfs.c

@@ -278,7 +278,7 @@ static char *sysfs_idlestate_get_one_string(unsigned int cpu,
 int sysfs_is_idlestate_disabled(unsigned int cpu,
 				unsigned int idlestate)
 {
-	if (sysfs_get_idlestate_count(cpu) < idlestate)
+	if (sysfs_get_idlestate_count(cpu) <= idlestate)
 		return -1;
 
 	if (!sysfs_idlestate_file_exists(cpu, idlestate,
@@ -303,7 +303,7 @@ int sysfs_idlestate_disable(unsigned int cpu,
 	char value[SYSFS_PATH_MAX];
 	int bytes_written;
 
-	if (sysfs_get_idlestate_count(cpu) < idlestate)
+	if (sysfs_get_idlestate_count(cpu) <= idlestate)
 		return -1;
 
 	if (!sysfs_idlestate_file_exists(cpu, idlestate,