This mode is supported through hw_mode_id 7. A special mode for
IPQ8074 platform alone to bring up single pdev alone on 2G mode.
FW would advertise the mode 7 support through the WMI service
ready message and this mode will be the default mode for AP-HK10 alone.
Added preferred_hw_mode and target_pdev_id into dp structures so that
they can be used to configure the dp rings for this particular mode.
Also changed the lmac_id to target_pdev_id mapping for mode 7.
Change-Id: I3aae46fea13132eebaf7d37cff68ef517253d229