Do some cleanup, including:
1. Remove DO_UPCAST() for APICCommonState
2. Change DeviceState pointers from 'd' to 'dev', better to understand
3. Rename 'register_types' to specifically 'apic_common_register_types'
Signed-off-by: xiaoqiang zhao <zxq_yx_007@163.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>