libpayload: Make Kconfig bools use IS_ENABLED()

This will make the code work with the different styles
of Kconfig (emit unset bools vs don't emit unset bools)

Roughly, the patch does this, and a little bit of fixing up:

perl -pi -e 's,ifdef (CONFIG_LP_.+?)\b,if IS_ENABLED\($1\),g' `find . -name *.[ch]`
perl -pi -e 's,ifndef (CONFIG_LP_.+?)\b,if !IS_ENABLED\($1\),g' `find . -name *.[ch]`

Change-Id: Ib8a839b056a1f806a8597052e1b571ea3d18a79f
Signed-off-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-on: http://review.coreboot.org/10711
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
diff --git a/payloads/libpayload/drivers/usb/xhci.c b/payloads/libpayload/drivers/usb/xhci.c
index 89930e0..f336f4d 100644
--- a/payloads/libpayload/drivers/usb/xhci.c
+++ b/payloads/libpayload/drivers/usb/xhci.c
@@ -88,7 +88,7 @@
 }
 
 /* On Panther Point: switch ports shared with EHCI to xHCI */
-#ifdef CONFIG_LP_USB_PCI
+#if IS_ENABLED(CONFIG_LP_USB_PCI)
 static void
 xhci_switch_ppt_ports(pcidev_t addr)
 {
@@ -112,7 +112,7 @@
 }
 #endif
 
-#ifdef CONFIG_LP_USB_PCI
+#if IS_ENABLED(CONFIG_LP_USB_PCI)
 /* On Panther Point: switch all ports back to EHCI */
 static void
 xhci_switchback_ppt_ports(pcidev_t addr)
@@ -296,7 +296,7 @@
 	return NULL;
 }
 
-#ifdef CONFIG_LP_USB_PCI
+#if IS_ENABLED(CONFIG_LP_USB_PCI)
 hci_t *
 xhci_pci_init (pcidev_t addr)
 {
@@ -411,7 +411,7 @@
 	xhci_t *const xhci = XHCI_INST(controller);
 	xhci_stop(controller);
 
-#ifdef CONFIG_LP_USB_PCI
+#if IS_ENABLED(CONFIG_LP_USB_PCI)
         if (controller->pcidev)
 		xhci_switchback_ppt_ports(controller->pcidev);
 #endif