raw/ioat: fix queue index calculation

raw/ioat: fix queue index calculation

Coverity flags a possible problem where the 8-bit wq_idx value may have
errors when shifted and sign-extended to pointer size. Since this can
only occur if the shift index is larger than any expected value from
hardware, it's unlikely to cause any real problems, but we can eliminate
any possible errors, and the coverity issue, by explicitly typecasting
the uint8_t value to uintptr_t before any shift operations occur.

Coverity issue: 363695
Fixes: a33969462135 ("raw/ioat: fix work-queue config size")

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>