Bug#789952: This is also an issue with 6300

[eigilhs@math.uio.no (Eigil Skjæveland)]

Same problem here. It always says 1 Mb/s.

$ uname -a
Linux thinkpad 4.0.0-2-amd64 #1 SMP Debian 4.0.8-2 (2015-07-22) x86_64 GNU/Linux

$ sudo iwconfig wlan0
wlan0     IEEE 802.11abgn  ESSID:"NAME"  
          Mode:Managed  Frequency:2.467 GHz  Access Point: 14:D6:4D:E3:FC:60   
          Bit Rate=1 Mb/s   Tx-Power=15 dBm   
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Encryption key:off
          Power Management:off
          Link Quality=70/70  Signal level=-38 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:204  Invalid misc:53   Missed beacon:0

$ sudo dmesg | grep iwlwifi | head
[    2.728248] iwlwifi 0000:02:00.0: can't disable ASPM; OS doesn't have ASPM control
[    2.732117] iwlwifi 0000:02:00.0: firmware: direct-loading firmware iwlwifi-6000-4.ucode
[    2.733113] iwlwifi 0000:02:00.0: loaded firmware version 9.221.4.1 build 25532 op_mode iwldvm
[    2.763053] iwlwifi 0000:02:00.0: CONFIG_IWLWIFI_DEBUG disabled
[    2.763130] iwlwifi 0000:02:00.0: CONFIG_IWLWIFI_DEBUGFS disabled
[    2.763205] iwlwifi 0000:02:00.0: CONFIG_IWLWIFI_DEVICE_TRACING disabled
[    2.763283] iwlwifi 0000:02:00.0: Detected Intel(R) Centrino(R) Ultimate-N 6300 AGN, REV=0x74
[    2.763503] iwlwifi 0000:02:00.0: L1 Enabled - LTR Disabled
[   74.391444] iwlwifi 0000:02:00.0: L1 Enabled - LTR Disabled
[   74.400438] iwlwifi 0000:02:00.0: Radio type=0x0-0x3-0x1