Change the data type of tci_tb_ptr, so GETPC() returns an
uintptr_t now (like for all other TCG targets).

This completes commit 20503968
and fixes builds with TCI.
Signed-off-by: NStefan Weil <sw@weilnetz.de>
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>