[lvgl] Allow multiple LVGL instances (#7712)

Co-authored-by: clydeps <U5yx99dok9>

tests/components/lvgl/test.host.yaml

@@ -1,5 +1,12 @@
 display:
   - platform: sdl
+    id: sdl0
+    auto_clear_enabled: false
+    dimensions:
+      width: 480
+      height: 320
+  - platform: sdl
+    id: sdl1
     auto_clear_enabled: false
     dimensions:
       width: 480
@@ -7,5 +14,30 @@ display:
 
 touchscreen:
   - platform: sdl
+    display: sdl0
+    sdl_id: sdl0
 
 lvgl:
+  - id: lvgl_0
+    displays: sdl0
+  - id: lvgl_1
+    displays: sdl1
+    on_idle:
+      timeout: 8s
+      then:
+        if:
+          condition:
+            lvgl.is_idle:
+              lvgl_id: lvgl_1
+              timeout: 5s
+          then:
+            logger.log: Lvgl2 is idle
+    widgets:
+      - button:
+          align: center
+          widgets:
+            - label:
+                text: Click ME
+          on_click:
+            logger.log: Clicked
+