powercap: Replace sprintf() with sysfs_emit() in sysfs show functions

Replace all sprintf() calls with sysfs_emit() in sysfs show functions.

sysfs_emit() is preferred over sprintf() for formatting sysfs output
as it provides better bounds checking and prevents potential buffer
overflows.

Also, replace sprintf() with sysfs_emit() in show_constraint_name()
and simplify the code by removing the redundant strlen() call since
sysfs_emit() returns the length.

Signed-off-by: Sumeet Pawnikar <sumeet4linux@gmail.com>
Link: https://patch.msgid.link/20260111141237.12340-1-sumeet4linux@gmail.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: sumeet4linux

drivers/powercap/powercap_sys.c

@@ -27,7 +27,7 @@ static ssize_t _attr##_show(struct device *dev, \
 	\
 	if (power_zone->ops->get_##_attr) { \
 		if (!power_zone->ops->get_##_attr(power_zone, &value)) \
-			len = sprintf(buf, "%lld\n", value); \
+			len = sysfs_emit(buf, "%lld\n", value); \
 	} \
 	\
 	return len; \
@@ -75,7 +75,7 @@ static ssize_t show_constraint_##_attr(struct device *dev, \
 	pconst = &power_zone->constraints[id]; \
 	if (pconst && pconst->ops && pconst->ops->get_##_attr) { \
 		if (!pconst->ops->get_##_attr(power_zone, id, &value)) \
-			len = sprintf(buf, "%lld\n", value); \
+			len = sysfs_emit(buf, "%lld\n", value); \
 	} \
 	\
 	return len; \
@@ -171,9 +171,8 @@ static ssize_t show_constraint_name(struct device *dev,
 	if (pconst && pconst->ops && pconst->ops->get_name) {
 		name = pconst->ops->get_name(power_zone, id);
 		if (name) {
-			sprintf(buf, "%.*s\n", POWERCAP_CONSTRAINT_NAME_LEN - 1,
-				name);
-			len = strlen(buf);
+			len = sysfs_emit(buf, "%.*s\n",
+					 POWERCAP_CONSTRAINT_NAME_LEN - 1, name);
 		}
 	}
 
@@ -350,7 +349,7 @@ static ssize_t name_show(struct device *dev,
 {
 	struct powercap_zone *power_zone = to_powercap_zone(dev);
 
-	return sprintf(buf, "%s\n", power_zone->name);
+	return sysfs_emit(buf, "%s\n", power_zone->name);
 }
 
 static DEVICE_ATTR_RO(name);
@@ -438,7 +437,7 @@ static ssize_t enabled_show(struct device *dev,
 				mode = false;
 	}
 
-	return sprintf(buf, "%d\n", mode);
+	return sysfs_emit(buf, "%d\n", mode);
 }
 
 static ssize_t enabled_store(struct device *dev,