crypto: msm: Use scnprintf() instead of snprintf()

snprintf can return more than the size of buffer, which is not
expected here, obviously. Use scnprintf instead.

Change-Id: I3b97a016df910728dfef5a0914ab8ad67c68e39c
Signed-off-by: AnilKumar Chimata <anilc@codeaurora.org>
crypto: msm: Add support for setting ctx flags

Currently there is no way of instructing the crypto driver
to use HW specific capabilities. The kernel crypto framework
does not expose any API to set any specific HW feature flags:
ex: use of HW key,  use of PIPE keys, setting XTS data unit
size.

The driver currently uses a specific key pattern to decide
when to instruct HW to use HW_KEY (uses key pattern of all
zeros) and when to use PIPE_KEY (uses key pattern of all 0xF's).
This limits the use of the specific key pattern from ever being
used for any crypto operation.

Adding support for crypto client to set flags to indicate when
to use HW KEY, PIPE KEY, size removes the limitation on the key
patterns that can be used by the driver.

Adding XTS data unit size flags allows the client to take
advantage of the hardware capability to set data unit size
for XTS operations.

Change-Id: I0d1417a6d3c990e0750dbd90e3816f45fec8d693
Signed-off-by: Mona Hossain <mhossain@codeaurora.org>

Conflicts:

	drivers/crypto/msm/qce50.c