Allowed frequency list configuration for AP operation

Allowed frequency list configuration for AP operation

Add support to configure the allowed frequency list for AP operation
using a QCA vendor interface before NL80211_CMD_NEW_BEACON/
NL80211_CMD_START_AP. hostapd generates the allowed frequency list by
intersecting user configured frequency list and all the frequencies
advertised by the driver including disabled channels. If user doesn't
specify allowed frequency list, all the frequencies advertised by the
driver, including disabled channels, will be configured.

Signed-off-by: Veerendranath Jakkam <quic_vjakkam@quicinc.com>