xhci: improve PORTSC register debugging output

Print the full hex value of PORTSC register in addition to the human
readable decoded string while debugging PORTSC value.

If PORTSC value is 0xffffffff then don't decode it.
This lets us inspect Rsvd bits of PORTSC.
Same is done for USBSTS register values.

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20240429140245.3955523-9-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>