dont need splvm in pool_gc_pages

[David Gwynne]

jmatthew@ noticed that i still had this code in here, despite making
it mandatory for pools to specify the IPL they operate at.

ok?

Index: subr_pool.c
===================================================================
RCS file: /cvs/src/sys/kern/subr_pool.c,v
retrieving revision 1.205
diff -u -p -r1.205 subr_pool.c
--- subr_pool.c 24 Jan 2017 09:54:41 -0000      1.205
+++ subr_pool.c 7 Feb 2017 07:25:19 -0000
@@ -1446,10 +1446,8 @@ pool_gc_pages(void *null)
 {
        struct pool *pp;
        struct pool_page_header *ph, *freeph;
-       int s;
 
        rw_enter_read(&pool_lock);
-       s = splvm(); /* XXX go to splvm until all pools _setipl properly */
        SIMPLEQ_FOREACH(pp, &pool_head, pr_poollist) {
                if (pp->pr_nidle <= pp->pr_minpages || /* guess */
                    !mtx_enter_try(&pp->pr_mtx)) /* try */
@@ -1469,7 +1467,6 @@ pool_gc_pages(void *null)
                if (freeph != NULL)
                        pool_p_free(pp, freeph);
        }
-       splx(s);
        rw_exit_read(&pool_lock);
 
        timeout_add_sec(&pool_gc_tick, 1);