hw/i386/pc.c: add description for fd-bootchk option

The 'fd-bootchk' option for pc and q35 machines currently lacks of
description in the help output. This makes it difficult for users
to understand the purpose of the command.

This commit solve this issue by adding description using
object_class_property_set_description() in hw/i386/pc.c,
adding the the description message for the option 'fd-bootchk'.

Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Suggested-by: Thomas Huth <thuth@redhat.com>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/3193
Signed-off-by: Choon Keong <ckeong.teo17@gmail.com>
Message-ID: <20260211162909.6550-1-ckeong.teo17@gmail.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

hw/i386/pc.c

@@ -1822,6 +1822,8 @@ static void pc_machine_class_init(ObjectClass *oc, const void *data)
     object_class_property_add_bool(oc, "fd-bootchk",
         pc_machine_get_fd_bootchk,
         pc_machine_set_fd_bootchk);
+    object_class_property_set_description(oc, "fd-bootchk",
+        "Enable/disable boot signature checking for floppy disks in BIOS");
 
 #if defined(CONFIG_IGVM)
     object_class_property_add_link(oc, "igvm-cfg",