include/exec: Use uintptr_t in CPUTLBEntry

include/exec: Use uintptr_t in CPUTLBEntry

Since we no longer support 64-bit guests on 32-bit hosts,
we can use a 32-bit type on a 32-bit host.  This shrinks
the size of the structure to 16 bytes on a 32-bit host.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>