PCI: designware: Fix PORT_LOGIC_LINK_WIDTH_MASK

The value under PORT_LOGIC_LINK_WIDTH_MASK is 0x1, 0x2, 0x4, 0x8.  In IP
v4.2, bits [16:8] are defined for NUM_OF_LANES.  But in IP v4.4, bits[12:8]
are defined for NUM_OF_LANES, bits [16:13] are for other usages (bit 16 is
AUTO_LANE_FLIP_CTRL_EN, bits [15:13] are PRE_DET_LANE).

As there is no conflict about NUM_OF_LANES between v4.2 and v4.4, change
the mask value to avoid future problems.

Signed-off-by: Zhou Wang <wangzhou1@hisilicon.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Jingoo Han <jingoohan1@gmail.com>