xhci: Limit USB2 port wake support for AMD Promontory hosts

For AMD Promontory xHCI host, although you can disable USB 2.0 ports in
BIOS settings, those ports will be enabled anyway after you remove a
device on that port and re-plug it in again. It's a known limitation of
the chip. As a workaround we can clear the PORT_WAKE_BITS.

This will disable wake on connect, disconnect and overcurrent on
AMD Promontory USB2 ports

[checkpatch cleanup and commit message reword -Mathias]
Cc: <stable@vger.kernel.org>
Cc: Tsai Nicholas <nicholas.tsai@amd.com>
Signed-off-by: Jiahau Chang <Lars_Chang@asmedia.com.tw>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>