reg_get_channel_list_with_power function is a redundant function as its
counterpart reg_get_channel_list_with_power_for freq have the same
functionality. Also the two functions have almost the same implementation.
Therefore removing the function reg_get_channel_list_with_power.
Also added the assignment of the variable "chan_num" to the function
reg_get_channel_list_with_power_for_freq, as the assignment was missing.
CRs-Fixed: 2738838
Change-Id: Ifd2fd795cacd89989e1755f3b8fd56ccd7d5b84f
dcb1efdcce