drivers: thermal: fix invalid buffer size on boost_store

Signed-off-by: Nanda Oktavera <codeharuka.yusa@gmail.com>

drivers/thermal/thermal_core.c

@@ -2691,7 +2691,7 @@ thermal_boost_store(struct device *dev,
 				      struct device_attribute *attr, const char *buf, size_t len)
 {
 	int ret;
-	ret = snprintf(boost_buf, PAGE_SIZE, buf);
+	ret = snprintf(boost_buf, sizeof(boost_buf), buf);
 	return len;
 }