PCI: endpoint: Fix configfs group list head handling

PCI: endpoint: Fix configfs group list head handling

commit d79123d79a8154b4318529b7b2ff7e15806f480b upstream.

Doing a list_del() on the epf_group field of struct pci_epf_driver in
pci_epf_remove_cfs() is not correct as this field is a list head, not
a list entry. This list_del() call triggers a KASAN warning when an
endpoint function driver which has a configfs attribute group is torn
down:

==================================================================
BUG: KASAN: slab-use-after-free in pci_epf_remove_cfs+0x17c/0x198
Write of size 8 at addr ffff00010f4a0d80 by task rmmod/319

CPU: 3 UID: 0 PID: 319 Comm: rmmod Not tainted 6.16.0-rc2 #1 NONE
Hardware name: Radxa ROCK 5B (DT)
Call trace:
show_stack+0x2c/0x84 (C)
dump_stack_lvl+0x70/0x98
print_report+0x17c/0x538
kasan_report+0xb8/0x190
__asan_report_store8_noabort+0x20/0x2c
pci_epf_remove_cfs+0x17c/0x198
pci_epf_unregister_driver+0x18/0x30
nvmet_pci_epf_cleanup_module+0x24/0x30 [nvmet_pci_epf]
__arm64_sys_delete_module+0x264/0x424
invoke_syscall+0x70/0x260
el0_svc_common.constprop.0+0xac/0x230
do_el0_svc+0x40/0x58
el0_svc+0x48/0xdc
el0t_64_sync_handler+0x10c/0x138
el0t_64_sync+0x198/0x19c
...

Remove this incorrect list_del() call from pci_epf_remove_cfs().

Fixes: ef1433f717a2 ("PCI: endpoint: Create configfs entry for each pci_epf_device_id table entry")
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20250624114544.342159-2-dlemoal@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>