os/os-qnx: fix overwrite of 'errno'

os/os-qnx: fix overwrite of 'errno'

You can't call perror() and expect errno to retain the same value,
it'll be zero after that. On top of that, there's no reason to
print the error here, the higher up layers will do that when an error
is returned.

Fixes: 946733c6f19c ("Support QNX OS platform")
Signed-off-by: Jens Axboe <axboe@kernel.dk>