qed_ilt_shadow_alloc() will call qed_ilt_shadow_free() to
free p_hwfn->p_cxt_mngr->ilt_shadow on error. However,
qed_cxt_tables_alloc() accesses the freed pointer on failure
of qed_ilt_shadow_alloc() through calling qed_cxt_mngr_free(),
which may lead to use-after-free. Fix this issue by setting
p_mngr->ilt_shadow to NULL in qed_ilt_shadow_free().

Fixes: fe56b9e6 ("qed: Add module with basic common support")
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Link: https://lore.kernel.org/r/20231210045255.21383-1-dinghao.liu@zju.edu.cnSigned-off-by: Jakub Kicinski <kuba@kernel.org>