soc/riscv/riscv-ite/it8xxx2: Support DEVNULL_REGION

it8xxx2 uses a custom linker script, which was not updated on
dfb3674. This patch naively updates it
to support DEVNULL_REGION.

Signed-off-by: Ederson de Souza <ederson.desouza@intel.com>

soc/riscv/riscv-ite/it8xxx2/linker.ld

@@ -69,13 +69,19 @@
 #define SHA256_BLOCK_SIZE 0x200
 #endif
 
+#include <zephyr/linker/linker-devnull.h>
+
 MEMORY
 {
 #ifdef CONFIG_XIP
     ROM (rx)  : ORIGIN = ROM_BASE, LENGTH = ROM_SIZE
 #endif
     RAM (rwx) : ORIGIN = RAM_BASE, LENGTH = RAM_SIZE
 
+#if defined(CONFIG_LINKER_DEVNULL_MEMORY)
+    DEVNULL_ROM (rx) : ORIGIN = DEVNULL_ADDR, LENGTH = DEVNULL_SIZE
+#endif
+
     LINKER_DT_REGIONS()
 
     /* Used by and documented in include/linker/intlist.ld */