ANQP: Add support to specify frequency in ANQP_GET command

ANQP: Add support to specify frequency in ANQP_GET command

Previously, wpa_supplicant fetched BSS channel info from scan results to
send ANQP Query frames. If the scan results for the specified BSS are
not available, the ANQP_GET command request was getting rejected.

Add support to send ANQP Query frame on the specified frequency without
requiring the scan results to be available.

The control interface command format:
- ANQP_GET <dst_addr> [freq=<freq in MHz>] <Query ID1>[,<Query ID2>,..]

Signed-off-by: Veerendranath Jakkam <vjakkam@codeaurora.org>