mmc: cqhci: initialize upper 64 bits of 128-bit task descriptors

mmc: cqhci: initialize upper 64 bits of 128-bit task descriptors

Move the task descriptor initialization into cqhci_prep_task_desc().
In addition, make it explicitly initialize all 128 bits of the task
descriptor if the host controller is using 128-bit task descriptors,
rather than relying on the implicit zeroing from dmam_alloc_coherent().

This is needed to prepare for CQHCI inline encryption support, which
requires 128-bit task descriptors and uses the upper 64 bits.

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/20210126001456.382989-4-ebiggers@kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>