wifi: ath11k: fix soc_dp_stats debugfs file permission

wifi: ath11k: fix soc_dp_stats debugfs file permission

Currently the soc_dp_stats debugfs file has the following permissions:

# ls -l /sys/kernel/debug/ath11k/pci-0000:03:00.0/soc_dp_stats
-rw------- 1 root root 0 Mar  4 15:04 /sys/kernel/debug/ath11k/pci-0000:03:00.0/soc_dp_stats

However this file does not actually support write operations -- no .write()
method is registered. Therefore use the correct permissions when creating
the file.

After the change:

# ls -l /sys/kernel/debug/ath11k/pci-0000:03:00.0/soc_dp_stats
-r-------- 1 root root 0 Mar  4 15:15 /sys/kernel/debug/ath11k/pci-0000:03:00.0/soc_dp_stats

Tested-on: WCN6855 hw2.1 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.30

Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://msgid.link/20240305-fix-soc_dp_stats-permission-v1-1-2ec10b42f755@quicinc.com