dts: stm32wb: Delete useless sram definitions

sram2a and sram2b where defined in the prospect of defining
HCI shared memory sections from device tree.
Remove them, since this is not the case anymore.

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

Author: erwango

dts/arm/st/wb/stm32wb55Xg.dtsi

@@ -11,15 +11,6 @@
 		reg = <0x20000000 DT_SIZE_K(96)>;
 	};
 
-	sram2a:memory@20030000 {
-		reg = <0x20030000 0x2800>;
-	};
-
-	sram2b:memory@20038000 {
-		reg = <0x20038000 0x5000>;
-	};
-
-
 	soc {
 		flash-controller@58004000 {
 			flash0: flash@8000000 {