samples: modules: lvgl: update for ek_ra8p1 and ek_ra8d1

Add extra configs in sample.yaml to LVGL demos for Renesas
EK-RA8P1 and EK-RA8D1 boards.

Add new overlay file for EK-RA8P1 to adjust flash
partitions.

Author: khaicaorvc

samples/modules/lvgl/demos/boards/ek_ra8p1_r7ka8p1kflcac_cm85.overlay

@@ -0,0 +1,12 @@
+/*
+ * Copyright (c) 2025 Renesas Electronics Corporation
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&flash0 {
+	reg = <0x2000000 0x100000>;
+};
+
+&flash1 {
+	status = "disabled";
+};

samples/modules/lvgl/demos/sample.yaml

@@ -69,6 +69,10 @@ tests:
     extra_args: SHIELD=rtkmipilcdb00000be
     tags:
       - shield
+    extra_configs:
+      - CONFIG_LV_Z_DEMO_WIDGETS=y
+      - CONFIG_LV_USE_SYSMON=y
+      - CONFIG_LV_USE_PERF_MONITOR=y
   sample.modules.lvgl.demos.rtk7eka6m3b00001bu:
     platform_allow: ek_ra8d1
     extra_args:
@@ -87,6 +91,8 @@ tests:
       - SHIELD=rtklcdpar1s00001be
       - DTC_OVERLAY_FILE=rtklcdpar1s00001be.overlay
     extra_configs:
-      - CONFIG_LV_DEMO_MUSIC_LANDSCAPE=y
+      - CONFIG_LV_Z_DEMO_WIDGETS=y
+      - CONFIG_LV_USE_SYSMON=y
+      - CONFIG_LV_USE_PERF_MONITOR=y
     tags:
       - shield