xen-platform: Constify dev_pm_ops

dev_pm_ops is never modified, so mark it const to allow the compiler to
put it in read-only memory.

Before:
   text    data     bss     dec     hex filename
   2457    1668     256    4381    111d drivers/xen/platform-pci.o

After:
   text    data     bss     dec     hex filename
   2681    1444     256    4381    111d drivers/xen/platform-pci.o

Signed-off-by: Rikard Falkeborn <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Juergen Gross <[email protected]>
Signed-off-by: Boris Ostrovsky <[email protected]>

Author: rikardfalkeborn

drivers/xen/platform-pci.c

@@ -168,7 +168,7 @@ static const struct pci_device_id platform_pci_tbl[] = {
 	{0,}
 };
 
-static struct dev_pm_ops platform_pm_ops = {
+static const struct dev_pm_ops platform_pm_ops = {
 	.resume_noirq =   platform_pci_resume,
 };