While not the default case, multiple tests can be run simultaneously.
Then, data_ready being a global variable will be overwritten and the
per-instance lock will not help. Turn the global variable into a
per-instance one to avoid this problem.
Fixes: e339c80af9 ("mailbox: mailbox-test: don't rely on rx_buffer content to signal data ready")
Signed-off-by: Wolfram Sang <[email protected]>
Signed-off-by: Jassi Brar <[email protected]>