Wifi: Support of channel stats in HAL V1.3

Remove the max channel count limit to get all channel stats.

Bug: 151425271
Test: Verify on BRCM 43752 chip + hikey960,
      Fw needs update and will be included in next release (May 29th)
Change-Id: I4c672dfd77b46bae9f8e878a8ee98fbd0f01dac5
Signed-off-by: Winnie Chen <winnie.chen@broadcom.com>