boards: nucleo_wb55rg: Give more flash space to M0 binary

Since version 1.11.0, Full stack M0 binary requires 216K of flash
being available, while previously 212K were required.

Review flash partitioning to take it into account.
Additionally:
- update value in board yaml file.
- align value in package .dtsi file

Fixes #38735

Signed-off-by: Erwan Gouriou <[email protected]>

Author: erwango

boards/arm/nucleo_wb55rg/nucleo_wb55rg.dts

@@ -189,9 +189,9 @@ zephyr_udc0: &usb {
 		#address-cells = <1>;
 		#size-cells = <1>;
 
-		/* Set all partitions with first 812K of flash */
-		/* last 212K are reseved for M0 usage */
-		/* Configure partitions to make use of the whole 812K */
+		/* Set all partitions with first 808K of flash */
+		/* last 216K are reseved for M0 usage */
+		/* Configure partitions to make use of the whole 808K */
 
 		boot_partition: partition@0 {
 			label = "mcuboot";
@@ -211,7 +211,7 @@ zephyr_udc0: &usb {
 		};
 		storage_partition: partition@c8000 {
 			label = "storage";
-			reg = <0x000c8000 0x3000>;
+			reg = <0x000c8000 0x2000>;
 		};
 
 	};

dts/arm/st/wb/stm32wb55Xg.dtsi

@@ -14,7 +14,7 @@
 	soc {
 		flash-controller@58004000 {
 			flash0: flash@8000000 {
-				reg = <0x08000000 DT_SIZE_K(812)>;
+				reg = <0x08000000 DT_SIZE_K(808)>;
 			};
 		};
 	};