• Rename bluetooth coexistence flags, no binary change.
• Enable DC calibration and crystal calibration on Centrino Advanced-N 6250 parts.
• Workaround for a HW bug (does not affect 4965AGN) that may sporadically affect latency under some rare circumstances. From a similar commit to iwlwifi.
• Update sensitivity settings for 5000 series to workaround a performance bug in the DSP (1000 is not affected so we keep the old values for 5000).
• Update sensitivity settings for 6000 series.
• Set differential gains on 6250 too (but use a 1.0 factor, not 1.5).
• Init OFDM sensitivity with min value (which depends on the chip) instead of hardcoding it to 90.
• Read calibration version from ROM and set IWN_GP_DRIVER_CALIB_VER6 bit on 6x50 if version >= 6.

Approved by: rpaulo (mentor)
Obtained from: OpenBSD
MFC after: 2 weeks