Fix missing newline in sysfs file

When using cat command to read /sys/class/kxo/kxo/kxo_state file, the
output (e.g., "1 1 0") did not include a newline, causing the terminal
prompt to appear on the same line (e.g., "1 1 0user@Ubuntu:~$").

This truncation issue is diagnosed by examining kxo_state_show, which
uses snprintf with a format string "%c %c %c\n". The size parameter of
snprintf set to 6 included the null terminator \0 as the last character,
leaving only 5 bytes for the desired output (e.g., "1 0 0\n"), thus the
newline symbol \n was truncated by null terminator.

This commit resolves the issue by increasing the size parameter of
snprintf from 6 to 7, ensuring the output includes the newline.

Author: JeepWay

main.c

@@ -48,7 +48,7 @@ static ssize_t kxo_state_show(struct device *dev,
                               char *buf)
 {
     read_lock(&attr_obj.lock);
-    int ret = snprintf(buf, 6, "%c %c %c\n", attr_obj.display, attr_obj.resume,
+    int ret = snprintf(buf, 7, "%c %c %c\n", attr_obj.display, attr_obj.resume,
                        attr_obj.end);
     read_unlock(&attr_obj.lock);
     return ret;