tests: Provide the relevant fw_config.yaml for the tests requiring it

A few test create dummy devices via DEVICE_DEFINE, and a few of them
have actual initialization dependencies which was - before - solved
through a fixed priority number for each devices.

Fix this now via a dedicated fw_config.yaml in relevant tests, where
the dev_id (provided to DEVICE_DEFINE) can be used to describe the
inialization node and its dependencies.

Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@proton.me>

tests/drivers/ipm/fw_config.yaml

@@ -0,0 +1,8 @@
+init:
+    ipm_console_send0:
+        dependencies:
+            - ipm_dummy0
+
+    ipm_console_recv0:
+        dependencies:
+            - ipm_dummy0

tests/kernel/device/fw_config.yaml

@@ -0,0 +1,12 @@
+init:
+  my_driver_priority_2:
+    dependencies:
+      - my_driver_priority_1
+
+  my_driver_priority_3:
+    dependencies:
+      - my_driver_priority_2
+
+  my_driver_priority_4:
+    dependencies:
+      - my_driver_priority_3

tests/net/mld/fw_config.yaml

@@ -0,0 +1,4 @@
+init:
+  net_test_null_iface:
+    dependencies:
+      - net_init