samples: subsys: usb dfu cannot run on the stm32h7rs boards

Because the stm32h573i disco kit boards have partition in the external
memory the samples/subsys/usb/dfu cannot run on those target boards

Signed-off-by: Francois Ramu <[email protected]>

Author: FRASTM

samples/subsys/usb/dfu/sample.yaml

@@ -29,6 +29,7 @@ common:
     - frdm_mcxa156
     - lpcxpresso55s69/lpc55s69/cpu0
     - stm32l562e_dk/stm32l562xx/ns
+    - stm32h573i_dk
   depends_on: usb_device
   filter: dt_label_with_parent_compat_enabled("slot0_partition", "fixed-partitions")
     and dt_label_with_parent_compat_enabled("slot1_partition", "fixed-partitions")