afs: Remove check of PageError

If read_mapping_page() encounters an error, it returns an errno, not a
page with PageError set, so this is dead code.

Signed-off-by: Matthew Wilcox (Oracle) <[e-mail]>

fs/afs/mntpt.c

···
 		if (IS_ERR(page))
 			return PTR_ERR(page);
 
-		if (PageError(page)) {
-			ret = afs_bad(AFS_FS_I(d_inode(mntpt)), afs_file_error_mntpt);
-			put_page(page);
-			return ret;
-		}
-
 		buf = kmap(page);
 		ret = -EINVAL;
 		if (buf[size - 1] == '.')