crypto: marvell/cesa - fix uninit value for struct mv_cesa_op_ctx

In cesa/cipher.c most declarations of struct mv_cesa_op_ctx are uninitialized.
This causes one of the values in the struct to be left unitialized in later
usages.

This patch fixes it by adding initializations in the same way it is done in
cesa/hash.c.

Fixes errors discovered in coverity: 1600942, 1600939, 1600935, 1600934, 1600929, 1600927,
1600925, 1600921, 1600920, 1600919, 1600915, 1600914

Signed-off-by: Karol Przybylski <karprzy7@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>