Coverity warns that "ssi_transfer(s->spi, 0U) << 8 * i" might overflow
because the expression is evaluated using 32-bit arithmetic and then
used in a context expecting a uint64_t.
Fixes: Coverity CID 1487244
Message-Id: <20220628165512.1133590-1-clg@kaod.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>