qcacmn: Reverting type of channel number variables in ch_params

The variables center_freq_seg0 and center_freq_seg1 in struct
ch_params are used to represent channel numbers. Their types
were wrongly changed to qdf_freq_t in change ID
e205befb82f643808973286ae578d7add7738eec. Change their type
back to uint8_t.

Change-Id: I13c629850bf207c6088b44c8695167e96dc33476
1 file changed