Interworking: Select highest priority cred if multiple matches

Interworking: Select highest priority cred if multiple matches

Previously, the credential to use for a connection with a specific BSS
was picked arbitrary based on first found match of each matching
mechanism. While the credential priorities were used elsewhere, this did
not take into account that different mechanisms could find multiple
matching credentials. As such, the highest priority credential was not
always used in case more than one credential matched with the selected
BSS. Fix this by checking credential priorities again during connection
request.

Signed-hostap: Jouni Malinen <jouni@qca.qualcomm.com>