thermald: Fix build with clang 23

configure.ac appends -Werror on top of -Wall unless --disable-werror is
passed, so every warning a newer compiler learns turns into a hard build
failure.

clang 23 added -Wunused-but-set-global and enabled it under -Wall. It
fires on the "static gpointer <t_n>_parent_class = NULL" that glib's
G_DEFINE_TYPE() emits, which is assigned in the generated class_intern_init
but never read unless the type chains up to a parent vfunc. PrefObject in
thd_dbus_interface.cpp never does:

  src/thd_dbus_interface.cpp:48:1: error: variable 'pref_object_parent_class'
      set but not used [-Werror,-Wunused-but-set-global]
     48 | G_DEFINE_TYPE(PrefObject, pref_object, G_TYPE_OBJECT)

Pass --disable-werror, the escape hatch upstream added for exactly this,
rather than suppressing the individual warning - gcc does not know
-Wno-unused-but-set-global. OE's own -Werror=format-security is unaffected.

Signed-off-by: Khem Raj <khem.raj@oss.qualcomm.com>

meta-oe/recipes-bsp/thermald/thermald_2.5.12.bb

@@ -29,6 +29,7 @@ do_configure:prepend () {
 
 EXTRA_OECONF = " \
                  --with-systemdsystemunitdir=${systemd_system_unitdir} \
+                 --disable-werror \
                  "
 
 FILES:${PN} += "${datadir}/dbus-1"