fs: stop accessing ->i_count directly in f2fs and gfs2

Instead of accessing ->i_count directly in these file systems, use the
appropriate __iget and iput helpers.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/b8e6eb8a3e690ce082828d3580415bf70dfa93aa.1755806649.git.josef@toxicpanda.com


Signed-off-by: Christian Brauner <brauner@kernel.org>