shields: st_b_cams_imx_mb1854: set sensor conf if DCMIPP is enabled

Instead of having a conf file for all variants of STM32N6570_DK,
set the necessary settings for any platform which has DCMIPP enabled.

Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>

boards/shields/st_b_cams_imx_mb1854/Kconfig.defconfig

@@ -0,0 +1,17 @@
+# ST_B_CAMS_IMX_MB1854 configuration
+
+# Copyright (c) 2025 STMicroelectronics
+# SPDX-License-Identifier: Apache-2.0
+
+if VIDEO_STM32_DCMIPP
+
+config VIDEO_STM32_DCMIPP_SENSOR_PIXEL_FORMAT
+	default "pRAA"
+
+config VIDEO_STM32_DCMIPP_SENSOR_WIDTH
+	default 2592
+
+config VIDEO_STM32_DCMIPP_SENSOR_HEIGHT
+	default 1944
+
+endif # VIDEO_STM32_DCMIPP

boards/shields/st_b_cams_imx_mb1854/boards/stm32n6570_dk.conf

@@ -1,3 +0,0 @@
-CONFIG_VIDEO_STM32_DCMIPP_SENSOR_PIXEL_FORMAT="pRAA"
-CONFIG_VIDEO_STM32_DCMIPP_SENSOR_WIDTH=2592
-CONFIG_VIDEO_STM32_DCMIPP_SENSOR_HEIGHT=1944

boards/shields/st_b_cams_imx_mb1854/boards/stm32n6570_dk_stm32n657xx_sb.conf

@@ -1,3 +0,0 @@
-CONFIG_VIDEO_STM32_DCMIPP_SENSOR_PIXEL_FORMAT="pRAA"
-CONFIG_VIDEO_STM32_DCMIPP_SENSOR_WIDTH=2592
-CONFIG_VIDEO_STM32_DCMIPP_SENSOR_HEIGHT=1944