accel/tcg: Move PageDesc tree into tb-maint.c for system

Now that PageDesc is not used for user-only, and for system
it is only used for tb maintenance, move the implementation
into tb-main.c appropriately ifdefed.

We have not yet eliminated all references to PageDesc for
user-only, so retain a typedef to the structure without definition.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
3 files changed