samples/subsys: littlefs: Add disco_l475_iot1

Add disco_l475_iot1 as build platform for this sample

Signed-off-by: Erwan Gouriou <[email protected]>

Author: erwango

samples/subsys/fs/littlefs/sample.yaml

@@ -3,5 +3,5 @@ sample:
 tests:
   sample.filesystem.littlefs:
     build_only: true
-    platform_allow: nrf52840dk_nrf52840 particle_xenon
+    platform_allow: nrf52840dk_nrf52840 particle_xenon disco_l475_iot1
     tags: filesystem