wifi: ath12k: Fix end offset bit definition in monitor ring descriptor

wifi: ath12k: Fix end offset bit definition in monitor ring descriptor

End offset for the monitor destination ring descriptor is defined as
16 bits, while the firmware definition specifies only 12 bits.
The remaining bits (bit 12 to bit 15) are reserved and may contain
junk values, leading to invalid information retrieval. Fix this issue
by updating the correct genmask values.

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.3.1-00173-QCAHKSWPL_SILICONZ-1
Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3

Signed-off-by: P Praneesh <quic_ppranees@quicinc.com>
Link: https://patch.msgid.link/20241223060132.3506372-8-quic_ppranees@quicinc.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>