tests: i2s: Fix i2s_states_test test suite

1. Update the way test_i2s_state_error_neg test handles
RX overflow.
2. Clean up after test_i2s_state_stopping_neg test in case the
receiving channel is stuck in the STOPPING State if the data
was received prior to calling the STOP trigger.

Signed-off-by: Mahesh Mahadevan <mahesh.mahadevan@nxp.com>
1 file changed