PCI: mvebu: Use FIELD_PREP() with Link Width

mvebu_pcie_setup_hw() setups the Maximum Link Width field in the Link
Capabilities registers using an open-coded variant of FIELD_PREP() with
a literal in shift. Improve readability by using
FIELD_PREP(PCI_EXP_LNKCAP_MLW, ...).

Link: https://lore.kernel.org/r/20230919125648.1920-6-ilpo.jarvinen@linux.intel.comSigned-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/pci/controller/pci-mvebu.c

@@ -264,7 +264,7 @@ static void mvebu_pcie_setup_hw(struct mvebu_pcie_port *port)
 	 */
 	lnkcap = mvebu_readl(port, PCIE_CAP_PCIEXP + PCI_EXP_LNKCAP);
 	lnkcap &= ~PCI_EXP_LNKCAP_MLW;
-	lnkcap |= (port->is_x4 ? 4 : 1) << 4;
+	lnkcap |= FIELD_PREP(PCI_EXP_LNKCAP_MLW, port->is_x4 ? 4 : 1);
 	mvebu_writel(port, lnkcap, PCIE_CAP_PCIEXP + PCI_EXP_LNKCAP);
 
 	/* Disable Root Bridge I/O space, memory space and bus mastering. */