xen/ppc: add section for device information in linker script

Introduce a new `.dev.info` section in the PPC linker script to
handle device-specific information. This section is required by
common code (common/device.c: device_init(), device_get_class() ).
This section is aligned to `POINTER_ALIGN`, with `_sdevice` and `_edevice`
marking the start and end of the section, respectively.

Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
Acked-by: Shawn Anastasio <sanastasio@raptorengineering.com>

xen/arch/ppc/xen.lds.S

@@ -96,6 +96,8 @@ SECTIONS
         CONSTRUCTORS
     } :text
 
+    DT_DEV_INFO                       /* Devicetree based device info */
+
     . = ALIGN(PAGE_SIZE);             /* Init code and data */
     __init_begin = .;
     DECL_SECTION(.init.text) {