net: sungem: fix probe error cleanup

net: sungem: fix probe error cleanup

gem_init_one() calls gem_remove_one() when register_netdev() fails.
gem_remove_one() unregisters and frees resources owned by the net_device,
including the DMA block, MMIO mapping, PCI regions, and the net_device
itself. gem_init_one() then falls through to its own cleanup labels and
frees the same resources again.

Keep the register_netdev() error path in gem_init_one(): clear drvdata so
PM/remove paths do not see a half-registered device, remove the NAPI
instance added during probe, and let the existing cleanup labels release
the resources once.

The issue was found by a local static-analysis checker for probe error
paths. The reported path was manually inspected before sending this fix.

Compile-tested with CONFIG_SUNGEM=y. Runtime testing was not performed
because no sungem hardware is available.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Ruoyu Wang <ruoyuw560@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260623025759.3468566-1-ruoyuw560@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>