target/ppc: Avoid tcg_const_* in xxeval

Initialize a new temp instead of tcg_const_*.
Fix a pasto in a comment.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
1 file changed