tests: Use 10 retries for over-the-air broadcast connectivity

tests: Use 10 retries for over-the-air broadcast connectivity

The regular hwsim tests use both unicast and broadcast frames to test
the connectivity between 2 interfaces. For real hardware (remote hwsim
tests) the broadcast frames will sometimes not be seen by all connected
stations since they can be in low power mode during DTIM or because
broadcast frames are not ACKed. Use 10 retries for broadcast
connectivity tests for real hardware so that the test will pass if we
successfully received at least one of them.

Signed-off-by: Jonathan Afek <jonathanx.afek@intel.com>