Check supported types in wpas_mac_addr_rand_scan_set()
When setting scan with randomized MAC, check the requested scan type
against supported types, to ensure callers will not set an unsupported
type, since this can cause scan/connect failures later. It is better to
do this in wpas_mac_addr_rand_scan_set() instead of control interface
specific code to apply the constraint on all possible interfaces using
this setting.