crypto: mediatek - make hardware operation flow more efficient

This patch refines data structures, which are used to control engine's
data path, to make it more efficient. Hence current change are:

- gathers the broken pieces of structures 'mtk_aes_ct''mtk_aes_tfm'
into struct mtk_aes_info hence avoiding additional DMA-mapping.

- adds 'keymode' in struct mtk_aes_base_ctx. When .setkey() callback is
called, we store keybit setting in keymode. Doing so, there is no need
to check keylen second time in mtk_aes_info_init() / mtk_aes_gcm_info_init().

Besides, this patch also removes unused macro definitions and adds helper
inline function to write security information(key, IV,...) to info->state.

Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>