mmc: core: Add basic support for inline encryption

In preparation for adding CQHCI crypto engine (inline encryption)
support, add the code required to make mmc_core and mmc_block aware of
inline encryption.  Specifically:

- Add a capability flag MMC_CAP2_CRYPTO to struct mmc_host.  Drivers
  will set this if the host and driver support inline encryption.

- Embed a blk_keyslot_manager in struct mmc_host.  Drivers will
  initialize this (as a device-managed resource) if the host and driver
  support inline encryption.  mmc_block registers this keyslot manager
  with the request_queue of any MMC card attached to the host.

- Make mmc_block copy the crypto keyslot and crypto data unit number
  from struct request to struct mmc_request, so that drivers will have
  access to them.

- If the MMC host is reset, reprogram all the keyslots to ensure that
  the software state stays in sync with the hardware state.

Co-developed-by: Satya Tangirala <satyat@google.com>
Signed-off-by: Satya Tangirala <satyat@google.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Satya Tangirala <satyat@google.com>
Reviewed-and-tested-by: Peng Zhou <peng.zhou@mediatek.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20210126001456.382989-2-ebiggers@kernel.org


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>