arch: x86: Enable devicetree linker memory regions

A devicetree compatible "zephyr,memory-region" was introduced in commit
18ffcdcf74 to generate linker script
memory regions from devicetree. It was enabled on arm and riscv
architectures only; extend that support to x86.

Signed-off-by: Maureen Helm <maureen.helm@intel.com>

include/zephyr/arch/x86/memory.ld

@@ -28,6 +28,7 @@
 #define ARCH_X86_MEMORY_LD
 
 #include <zephyr/devicetree.h>
+#include <zephyr/linker/devicetree_regions.h>
 #include <zephyr/sys/mem_manage.h>
 
 /* Bounds of physical RAM from DTS */
@@ -88,6 +89,7 @@ MEMORY
      * physical ROM locations
      */
     RAM (wx)        : ORIGIN = KERNEL_BASE_ADDR, LENGTH = KERNEL_RAM_SIZE
+    LINKER_DT_REGIONS()
 
 #ifdef CONFIG_X86_64
     /* Special low-memory area for bootstrapping other CPUs from real mode */