ext4: remove unneeded if checks before kfree

kfree already checks if its argument is NULL. This fixes two
Coccinelle/coccicheck warnings reported by ifnullfree.cocci.

Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20240317153638.2136-2-thorsten.blum@toblux.com


Signed-off-by: Theodore Ts'o <tytso@mit.edu>