crypto: ccree - reduce kernel stack usage with clang

Building with clang for a 32-bit architecture runs over the stack
frame limit in the setkey function:

drivers/crypto/ccree/cc_cipher.c:318:12: error: stack frame size of 1152 bytes in function 'cc_cipher_setkey' [-Werror,-Wframe-larger-than=]

The problem is that there are two large variables: the temporary
'tmp' array and the SHASH_DESC_ON_STACK() declaration. Moving
the first into the block in which it is used reduces the
total frame size to 768 bytes, which seems more reasonable
and is under the warning limit.

Fixes: 63ee04c8 ("crypto: ccree - add skcipher support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-By: Gilad Ben-Yossef <gilad@benyossef.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>