ath11k: add support for WCN6855 hw2.1

Ath11k fails to probe WCN6855 hw2.1 chip:

[ 6.983821] ath11k_pci 0000:06:00.0: enabling device (0000 -> 0002)
[ 6.983841] ath11k_pci 0000:06:00.0: Unsupported WCN6855 SOC hardware version: 18 17

This is caused by the wrong bit mask setting of hardware major version:
for QCA6390/QCN6855, it should be BIT8-11, not BIT8-16, so change the
definition to GENMASK(11, 8).

Also, add a separate entry for WCN6855 hw2.1 in ath11k_hw_params.

Please note that currently WCN6855 hw2.1 shares the same firmwares
as hw2.0, so users of this chip need to create a symlink as below:

	ln -s hw2.0 hw2.1

Tested-on: WCN6855 hw2.1 PCI WLAN.HSP.1.1-01720.1-QCAHSPSWPL_V1_V2_SILICONZ_LITE-1
Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-01720.1-QCAHSPSWPL_V1_V2_SILICONZ_LITE-1
Tested-on: QCA6390 hw2.0 PCI WLAN.HST.1.0.1-01740-QCAHSTSWPLZ_V2_TO_X86-1

Fixes: 18ac1665

 ("ath11k: pci: check TCSR_SOC_HW_VERSION")
Signed-off-by: Baochen Qiang <quic_bqiang@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20211129025613.21594-1-quic_bqiang@quicinc.com