ext4: remove useless resetting io_end_size in mpage_process_page()

The command "make clang-analyzer" detects dead stores in
mpage_process_page() function.

Do not reset io_end_size to 0 in the current paths, as the function
exits on those paths without further using io_end_size.
Signed-off-by: Nghia Le <nghialm78@gmail.com>
Link: https://lore.kernel.org/r/20211025221803.3326-1-nghialm78@gmail.comSigned-off-by: Theodore Ts'o <tytso@mit.edu>

fs/ext4/inode.c

@@ -2241,7 +2241,6 @@ static int mpage_process_page(struct mpage_da_data *mpd, struct page *page,
 			mpd->map.m_len = 0;
 			mpd->map.m_flags = 0;
 			io_end_vec->size += io_end_size;
-			io_end_size = 0;
 
 			err = mpage_process_page_bufs(mpd, head, bh, lblk);
 			if (err > 0)
@@ -2266,7 +2265,6 @@ static int mpage_process_page(struct mpage_da_data *mpd, struct page *page,
 	} while (lblk++, (bh = bh->b_this_page) != head);
 
 	io_end_vec->size += io_end_size;
-	io_end_size = 0;
 	*map_bh = false;
 out:
 	*m_lblk = lblk;