Ext4Pkg: Add missing exit status in Ext4OpenDirent

Missing EFI_OUT_OF_RESOURCES exit status on failed Ext4CreateDentry
leads to NULL-pointer dereference in Ext4GetFileInfo (passing NULL
buffer in Ext4ReadDir)

Cc: Marvin Häuser <mhaeuser@posteo.de>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Cc: Vitaly Cheptsov <vit9696@protonmail.com>
Fixes: 21b18538 ("Ext4Pkg: Add a directory entry tree.")
Signed-off-by: Savva Mitrofanov <savvamtr@gmail.com>
Reviewed-by: Pedro Falcato <pedro.falcato@gmail.com>
Reviewed-by: Marvin Häuser <mhaeuser@posteo.de>