Since the nonstandard inline encryption support on Exynos SoCs requires
that raw cryptographic keys be copied into the PRDT, it is desirable to
zeroize those keys after each request to keep them from being left in
memory.  Therefore, add a quirk bit that enables the zeroization.

We could instead do the zeroization unconditionally.  However, using a
quirk bit avoids adding the zeroization overhead to standard devices.
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Peter Griffin <peter.griffin@linaro.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20240708235330.103590-6-ebiggers@kernel.orgReviewed-by: Alim Akhtar <alim.akhtar@samsung.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>