ath10k: add dynamic vlan support

Multicast/broadcast traffic destined for a particular vlan group will
always be encrypted in software. To enable dynamic VLANs, it requires
driver support for sending software encrypted packets.

In ath10k, sending software encrypted frames is allowed only when we insmod
the driver with cryptmode param set to 1, this configuration disables
hardware crypto and enables RAW mode implicitly. Since, enabling raw
mode has performance impact, this cannot be considered as an ideal
solution for supporting VLANs in the driver.

As an alternative take, in this approach, cryptographic keys for
unicast traffic (per peer PTKs) and keys for non-vlan group traffic
will be configured in hardware, allowing hardware encryption for unicast
and non-vlan group traffic. Only vlan group traffic will be encrypted in
software and pushed to the target with encap mode set to RAW in the TX
descriptors.

Not all firmwares can support this type of key configuration(having few
keys installed in hardware and few only in software); for this purpose a
new WMI service flag "WMI_SERVICE_PER_PACKET_SW_ENCRYPT" is introduced to
advertise this support.

Also, adding the logic required to send sw encrypted frames in raw mode.

Hardwares Tested : QCA9984, QCA988X
Firmwares Tested : 10.4-3.5.3-00057, 10.2.4-1.0-00042

Signed-off-by: Manikanta Pubbisetty <mpubbise@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>