mmc: cqhci: add cqhci_host_ops::program_key

mmc: cqhci: add cqhci_host_ops::program_key

On Snapdragon SoCs, the Linux kernel isn't permitted to directly access
the standard CQHCI crypto configuration registers.  Instead, programming
and evicting keys must be done through vendor-specific SMC calls.

To support this hardware, add a ->program_key() method to
'struct cqhci_host_ops'.  This allows overriding the standard CQHCI
crypto key programming / eviction procedure.

This is inspired by the corresponding UFS crypto support, which uses
these same SMC calls.  See commit 1bc726e26ef3 ("scsi: ufs: Add
program_key() variant op").

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/20210126001456.382989-6-ebiggers@kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>