drivers: staging: ccree: ISO C forbids casting to and from non-scalar

Fixes the following sparse warnings:
drivers/staging/ccree/ssi_hash.c:2447:24: warning: cast to non-scalar
drivers/staging/ccree/ssi_hash.c:2447:24: warning: cast from non-scalar
drivers/staging/ccree/ssi_hash.c:2448:28: warning: cast to non-scalar
drivers/staging/ccree/ssi_hash.c:2448:28: warning: cast from non-scalar

Signed-off-by: Raphaël Beamonte <raphael.beamonte@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>