exec/translation-block: Include missing 'exec/vaddr.h' header

exec/translation-block: Include missing 'exec/vaddr.h' header

'vaddr' type is declared in "exec/vaddr.h".
"exec/translation-block.h" uses this type without including
the corresponding header. It works because this header is
indirectly included, but won't work when the other headers
are refactored:

  include/exec/translation-block.h:56:5: error: unknown type name 'vaddr'
     56 |     vaddr pc;
        |     ^

Explitly include "exec/vaddr.h" to avoid such problem in a
few commits.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20241114011310.3615-4-philmd@linaro.org>