crypto: iaa - Fix potential use after free bug

The free_device_compression_mode(iaa_device, device_mode) function frees
"device_mode" but it iss passed to iaa_compression_modes[i]->free() a few
lines later resulting in a use after free.

The good news is that, so far as I can tell, nothing implements the
->free() function and the use after free happens in dead code.  But, with
this fix, when something does implement it, we'll be ready.  :)

Fixes: b190447e ("crypto: iaa - Add compression mode management along with fixed mode")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>