erofs: always use iget5_locked

As Christoph said [1] [2], "Just use the slightly
more complicated 32-bit version everywhere so that
you have a single actually tested code path.
And then remove this helper. "

[1] https://lore.kernel.org/r/20190829102426.GE20598@infradead.org/
[2] https://lore.kernel.org/r/20190902125320.GA16726@infradead.org/Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Link: https://lore.kernel.org/r/20190904020912.63925-25-gaoxiang25@huawei.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/erofs/inode.c

@@ -243,7 +243,6 @@ static int erofs_fill_inode(struct inode *inode, int isdir)
  * erofs nid is 64bits, but i_ino is 'unsigned long', therefore
  * we should do more for 32-bit platform to find the right inode.
  */
-#if BITS_PER_LONG == 32
 static int erofs_ilookup_test_actor(struct inode *inode, void *opaque)
 {
 	const erofs_nid_t nid = *(erofs_nid_t *)opaque;
@@ -258,20 +257,14 @@ static int erofs_iget_set_actor(struct inode *inode, void *opaque)
 	inode->i_ino = erofs_inode_hash(nid);
 	return 0;
 }
-#endif
 
 static inline struct inode *erofs_iget_locked(struct super_block *sb,
 					      erofs_nid_t nid)
 {
 	const unsigned long hashval = erofs_inode_hash(nid);
 
-#if BITS_PER_LONG >= 64
-	/* it is safe to use iget_locked for >= 64-bit platform */
-	return iget_locked(sb, hashval);
-#else
 	return iget5_locked(sb, hashval, erofs_ilookup_test_actor,
 		erofs_iget_set_actor, &nid);
-#endif
 }
 
 struct inode *erofs_iget(struct super_block *sb,