hw/cxl: Define cxl_fmws_get_all_sorted() stub

Add a stub for cxl_fmws_get_all_sorted() to fix building
a QEMU configured with the '--without-default-devices' option:

  Undefined symbols for architecture arm64:
    "_cxl_fmws_get_all_sorted", referenced from:
        _cxl_build_cedt in hw_acpi_cxl.c.o

Note, the CXL <-> ACPI Kconfig relationship is a bit convoluted.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20260423170229.64655-3-philmd@linaro.org>

hw/cxl/cxl-host-stubs.c

@@ -18,3 +18,8 @@ hwaddr cxl_fmws_set_memmap(hwaddr base, hwaddr max_addr)
 void cxl_fmws_update_mmio(void) {};
 
 const MemoryRegionOps cfmws_ops;
+
+GSList *cxl_fmws_get_all_sorted(void)
+{
+    g_assert_not_reached();
+}