wifi: ath12k: fix crash when unbinding

JIRA: https://issues.redhat.com/browse/RHEL-70414

commit 1304446
Author: Jose Ignacio Tornos Martinez <jtornosm@redhat.com>
Date:   Thu Oct 17 20:07:31 2024 +0200

    wifi: ath12k: fix crash when unbinding
    
    If there is an error during some initialization related to firmware,
    the function ath12k_dp_cc_cleanup is called to release resources.
    However this is released again when the device is unbinded (ath12k_pci),
    and we get:
    BUG: kernel NULL pointer dereference, address: 0000000000000020
    at RIP: 0010:ath12k_dp_cc_cleanup.part.0+0xb6/0x500 [ath12k]
    Call Trace:
    ath12k_dp_cc_cleanup
    ath12k_dp_free
    ath12k_core_deinit
    ath12k_pci_remove
    ...
    
    The issue is always reproducible from a VM because the MSI addressing
    initialization is failing.
    
    In order to fix the issue, just set to NULL the released structure in
    ath12k_dp_cc_cleanup at the end.
    
    cc: stable@vger.kernel.org
    Fixes: d889913 ("wifi: ath12k: driver for Qualcomm Wi-Fi 7 devices")
    Signed-off-by: Jose Ignacio Tornos Martinez <jtornosm@redhat.com>
    Link: https://patch.msgid.link/20241017181004.199589-2-jtornosm@redhat.com
    Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>

Signed-off-by: Jose Ignacio Tornos Martinez <jtornosm@redhat.com>

Author: jtornosm

drivers/net/wireless/ath/ath12k/dp.c

@@ -1241,6 +1241,7 @@ static void ath12k_dp_cc_cleanup(struct ath12k_base *ab)
 	}
 
 	kfree(dp->spt_info);
+	dp->spt_info = NULL;
 }
 
 static void ath12k_dp_reoq_lut_cleanup(struct ath12k_base *ab)