swaponoff: shrink

function                                             old     new   delta
.rodata                                           148469  148468      -1
swap_on_off_main                                     381     379      -2
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-3)               Total: -3 bytes
   text	   data	    bss	    dec	    hex	filename
 803030	   4090	   9504	 816624	  c75f0	busybox_old
 803027	   4090	   9504	 816621	  c75ed	busybox_unstripped
diff --git a/util-linux/swaponoff.c b/util-linux/swaponoff.c
index afad4ab..40f971d 100644
--- a/util-linux/swaponoff.c
+++ b/util-linux/swaponoff.c
@@ -96,12 +96,11 @@
 			 || hasmntopt(m, MNTOPT_NOAUTO) == NULL
 			) {
 #if ENABLE_FEATURE_SWAPON_PRI
-				char *p;
 				g_flags = 0; /* each swap space might have different flags */
-				p = strstr(m->mnt_opts, "pri=");
+				char *p = hasmntopt(m,"pri");
 				if (p) {
 					/* Max allowed 32767 (==SWAP_FLAG_PRIO_MASK) */
-					int swap_prio = MIN(bb_strtoull(p + 4 , NULL, 10), SWAP_FLAG_PRIO_MASK);
+					unsigned int swap_prio = MIN(bb_strtou(p + 4 , NULL, 10), SWAP_FLAG_PRIO_MASK);
 					/* We want to allow "NNNN,foo", thus errno == EINVAL is allowed too */
 					if (errno != ERANGE) {
 						g_flags = SWAP_FLAG_PREFER |