FROMLIST: scsi: ufs: add program_key() variant op

On Snapdragon SoCs, the Linux kernel isn't permitted to directly access
the standard UFS 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 ufs_hba_variant_ops'.  This allows overriding the UFS standard
key programming procedure.

Link: https://lore.kernel.org/r/20200110061634.46742-5-ebiggers@kernel.org


Bug: 137270441
Bug: 147259927
Change-Id: Ia561d5a51421baaf78de52a1eaec496093a0d0ad
Signed-off-by: Eric Biggers <ebiggers@google.com>