hwsim:  Support deleting hwsim by name.

More convenient than by index.

Signed-off-by: Ben Greear <greearb@candelatech.com>
hwsim:  Support creating radio with specific name.

Makes it easier to automate tests.

Signed-off-by: Ben Greear <greearb@candelatech.com>
hwsim:  support creating hwsim radio w/out vdev.

This way, you can create wlanX interfaces manually with
the desired name and don't have to worry about what the
kernel might call the auto-created one.   Should be helpful
for automated testing.

Signed-off-by: Ben Greear <greearb@candelatech.com>