When max virtual ap interfaces are configured in all the bands with
ACS and hostapd restart is done every 60s, a crash is observed at
random times.

In the above scenario, a fragmented packet is received for self peer,
for which rx_tid and rx_frags are not initialized in datapath.
While handling this fragment, crash is observed as the rx_frag list
is uninitialized and when we walk in ath12k_dp_rx_h_sort_frags,
skb null leads to exception.

To address this, before processing received fragments we check
dp_setup_done flag is set to ensure that peer has completed its
dp peer setup for fragment queue, else ignore processing the
fragments.

Call trace:
    PC points to "ath12k_dp_process_rx_err+0x4e8/0xfcc [ath12k]"
    LR points to "ath12k_dp_process_rx_err+0x480/0xfcc [ath12k]".
    The Backtrace obtained is as follows:
    ath12k_dp_process_rx_err+0x4e8/0xfcc [ath12k]
    ath12k_dp_service_srng+0x78/0x260 [ath12k]
    ath12k_pci_write32+0x990/0xb0c [ath12k]
    __napi_poll+0x30/0xa4
    net_rx_action+0x118/0x270
    __do_softirq+0x10c/0x244
    irq_exit+0x64/0xb4
    __handle_domain_irq+0x88/0xac
    gic_handle_irq+0x74/0xbc
    el1_irq+0xf0/0x1c0
    arch_cpu_idle+0x10/0x18
    do_idle+0x104/0x248
    cpu_startup_entry+0x20/0x64
    rest_init+0xd0/0xdc
    arch_call_rest_init+0xc/0x14

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.0.1-00029-QCAHKSWPL_SILICONZ-1
Signed-off-by: Harshitha Prem <quic_hprem@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20230821130343.29495-2-quic_hprem@quicinc.com