P2P: Use only the -m config for P2P management device

P2P: Use only the -m config for P2P management device

Previously, the case of non-netdev P2P management device ended up
pulling in both the main interface (e.g., wlan0) and P2P Device
interface (from command line -m argument) as configuration. Similarly,
the main interface ended up included both configuration files. This is
not really helpful for various use cases, e.g., when permanent P2P group
information is stored in the P2P Devince interface, but it gets
duplicated in the main station interface configuration.

Clean this up by changing the -m<file> argument to replace, not
concatenate, configuration information. In other words, the main station
interface will not read this configuration and the P2P Device interface
(non-netdev) does not read parameters from the station interface
configuration file.

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