netdevsim: make array res_ids static const, makes object smaller

Don't populate the array res_ids on the stack but instead it
static const. Makes the object code smaller by 14 bytes.

Before:
   text    data     bss     dec     hex filename
  50833    8314     256   59403    e80b ./drivers/net/netdevsim/fib.o

After:
   text    data     bss     dec     hex filename
  50755    8378     256   59389    e7fd ./drivers/net/netdevsim/fib.o

(gcc version 10.2.0)
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20210801065328.138906-1-colin.king@canonical.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>

drivers/net/netdevsim/fib.c

@@ -1441,7 +1441,7 @@ static u64 nsim_fib_nexthops_res_occ_get(void *priv)
 static void nsim_fib_set_max_all(struct nsim_fib_data *data,
 				 struct devlink *devlink)
 {
-	enum nsim_resource_id res_ids[] = {
+	static const enum nsim_resource_id res_ids[] = {
 		NSIM_RESOURCE_IPV4_FIB, NSIM_RESOURCE_IPV4_FIB_RULES,
 		NSIM_RESOURCE_IPV6_FIB, NSIM_RESOURCE_IPV6_FIB_RULES,
 		NSIM_RESOURCE_NEXTHOPS,