crypto: Remove useless attribute

There is no need of 2 level status reporting, returned code from
synchronous call or the status code in the async callback should be
enough to tell why it did not work.

And this attribute is anyway unused anywhere.

This helps to save 4 bytes, in total, out of struct cipher_pkt.
(3 bytes were lurking around as the status attribute was only 1 byte).

Change-Id: Iadfe20d6b84d57d86683bc86203ce2ed50e40461
Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>