PM/devfreq: governor: add missing MODULE_DESCRIPTION() macros

make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/devfreq/governor_simpleondemand.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/devfreq/governor_performance.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/devfreq/governor_powersave.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/devfreq/governor_userspace.o

Add all missing invocations of the MODULE_DESCRIPTION() macro.

Link: https://lore.kernel.org/lkml/20240605-md-drivers-devfreq-v1-1-d01ae91b907e@quicinc.com/Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>

drivers/devfreq/governor_performance.c

@@ -58,4 +58,5 @@ static void __exit devfreq_performance_exit(void)
 	return;
 }
 module_exit(devfreq_performance_exit);
+MODULE_DESCRIPTION("DEVFREQ Performance governor");
 MODULE_LICENSE("GPL");

drivers/devfreq/governor_powersave.c

@@ -58,4 +58,5 @@ static void __exit devfreq_powersave_exit(void)
 	return;
 }
 module_exit(devfreq_powersave_exit);
+MODULE_DESCRIPTION("DEVFREQ Powersave governor");
 MODULE_LICENSE("GPL");

drivers/devfreq/governor_simpleondemand.c

@@ -140,4 +140,5 @@ static void __exit devfreq_simple_ondemand_exit(void)
 	return;
 }
 module_exit(devfreq_simple_ondemand_exit);
+MODULE_DESCRIPTION("DEVFREQ Simple On-demand governor");
 MODULE_LICENSE("GPL");

drivers/devfreq/governor_userspace.c

@@ -153,4 +153,5 @@ static void __exit devfreq_userspace_exit(void)
 	return;
 }
 module_exit(devfreq_userspace_exit);
+MODULE_DESCRIPTION("DEVFREQ Userspace governor");
 MODULE_LICENSE("GPL");