EDAC/igen6: Fix error handling in igen6_edac driver

EDAC/igen6: Fix error handling in igen6_edac driver

The igen6_edac driver calls device_initialize() for all memory
controllers in igen6_register_mci(), but misses corresponding
put_device() calls in error paths and during normal shutdown in
igen6_unregister_mcis().

Adding the missing put_device() calls improves code readability and
ensures proper reference counting for the device structure.

Found by code review.

Signed-off-by: Ma Ke <make24@iscas.ac.cn>
Reviewed-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Link: https://patch.msgid.link/20251105090244.23327-1-make24@iscas.ac.cn