modules: tf-m: lower minimum allowed CONFIG_TFM_ITS_MAX_ASSET_SIZE

Lower the minimum value allowed from 512 to 256 as the secure_storage
tests use 256 and this is still quite a reasonable minimum value
to have.

Signed-off-by: Tomi Fontanilles <[email protected]>

Author: tomi-font

modules/trusted-firmware-m/Kconfig

@@ -188,7 +188,7 @@ config TFM_ITS_VALIDATE_METADATA_FROM_FLASH
 	  Validate filesystem metadata every time it is read from flash
 
 config TFM_ITS_MAX_ASSET_SIZE
-	range 512 4096
+	range 256 4096
 	default 512
 	help
 	  The maximum asset size to be stored in the Internal Trusted Storage. The maximum value