Always trap for accessing IO port at CONFIG_SERIAL_PIO_BASE(0x3f8).
SOS will trap at IO 0x3f8 access because vuart[0]. When HW platform
has this serial IO port, and HV use it as debug shell, If vuart[0]
is not set, SOS & HV console input/output are mixed up.
So SOS should always trap at CONFIG_SERIAL_PIO_BASE
Tracked-On: #5498
Signed-off-by: Tao Yuhong <yuhong.tao@intel.com>