linux-user/ppc: Narrow type of ccr in save_user_regs

Coverity warns that we shift a 32-bit value by N, and then
accumulate it into a 64-bit type (target_ulong on ppc64).

The ccr is always 8 * 4-bit fields, and thus is always a
32-bit quantity; narrow the type to avoid the warning.

Fixes: Coverity CID 1487223
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20220401191643.330393-1-richard.henderson@linaro.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>