netlabel: remove impossible return value in netlbl_bitmap_walk

Since commit 446fda4f2682 ("[NetLabel]: CIPSOv4 engine"), *bitmap_walk
function only returns -1. Nearly 18 years have passed, -2 scenes never
come up, so there's no need to consider it.

Signed-off-by: Zhengchao Shao <[e-mail]>
Reviewed-by: Jiri Pirko <[e-mail]>
Acked-by: Paul Moore <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

net/ipv4/cipso_ipv4.c

···
 					      net_clen_bits,
 					      net_spot + 1,
 					      1);
-		if (net_spot < 0) {
-			if (net_spot == -2)
-				return -EFAULT;
+		if (net_spot < 0)
 			return 0;
-		}
 
 		switch (doi_def->type) {
 		case CIPSO_V4_MAP_PASS:

net/ipv6/calipso.c

···
 					  net_clen_bits,
 					  spot + 1,
 					  1);
-		if (spot < 0) {
-			if (spot == -2)
-				return -EFAULT;
+		if (spot < 0)
 			return 0;
-		}
 
 		ret_val = netlbl_catmap_setbit(&secattr->attr.mls.cat,
 					       spot,

net/netlabel/netlabel_kapi.c

···
  * Description:
  * Starting at @offset, walk the bitmap from left to right until either the
  * desired bit is found or we reach the end.  Return the bit offset, -1 if
- * not found, or -2 if error.
+ * not found.
  */
 int netlbl_bitmap_walk(const unsigned char *bitmap, u32 bitmap_len,
 		       u32 offset, u8 state)