erofs: kill prio and nofail of erofs_get_meta_page()

As Christoph pointed out [1],
"Why is there __erofs_get_meta_page with the two weird
booleans instead of a single erofs_get_meta_page that
gets and gfp_t for additional flags and an unsigned int
for additional bio op flags."

And since all callers can handle errors, let's kill
prio and nofail and erofs_get_inline_page() now.

[1] https://lore.kernel.org/r/20190830162812.GA10694@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Link: https://lore.kernel.org/r/20190904020912.63925-17-gaoxiang25@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/erofs/inode.c

@@ -182,7 +182,7 @@ static int fill_inode(struct inode *inode, int isdir)
 	debugln("%s, reading inode nid %llu at %u of blkaddr %u",
 		__func__, vi->nid, ofs, blkaddr);
 
-	page = erofs_get_meta_page(inode->i_sb, blkaddr, isdir);
+	page = erofs_get_meta_page(inode->i_sb, blkaddr);
 
 	if (IS_ERR(page)) {
 		errln("failed to get inode (nid: %llu) page, err %ld",