RTC6226: set the the Channel spacing value in Radio Config register

Channel spacing value is not updated to Radio
Config register.This leads to scan all valid station
in scan list.
Update the the Channel spacing value in Radio Config
register as per rtc6226 driver data sheet.

CRs-Fixed: 2721208
Change-Id: I40b3a32c916714b4db15279b7e6abaa22b85afad
Signed-off-by: himta ram <hram@codeaurora.org>