qcacmn: List 2G frequency list in scan_config command

scan_config command for 2G pdev was not listing 2GHz frequencies.
Fix frequency range check condition in is_chan_enabled_for_scan() to
include 2G frequency in the scan channel list.

Change-Id: I9883583505ab318328999c5cf2dd33e687a784b2
CRs-Fixed: 2350530