wifi(interface): Link layer stats collection

Add HIDL methods for STA iface link layer stats.

While there,
Add the missing gscan API for fetching a list of channels for a given
band.

Bug:31991459
Test: Compiles
Change-Id: I5d448eb823faae4e8f5c25f746cf59e70df454cf
diff --git a/wifi/1.0/IWifiChip.hal b/wifi/1.0/IWifiChip.hal
index 166cfb4..2a9ed49 100644
--- a/wifi/1.0/IWifiChip.hal
+++ b/wifi/1.0/IWifiChip.hal
@@ -174,7 +174,7 @@
    * Must trigger |IWifiChipEventCallback.onChipReconfigured| on success.
    * Must trigger |IWifiEventCallback.onFailure| on failure.
    *
-   * @param modeId The mode that the chip should switch to, corresponding to the
+   * @param modeId The mode that the chip must switch to, corresponding to the
    *        id property of the target ChipMode.
    * @return status WifiStatus of the operation.
    *         Possible status codes: