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/ehci.c b/payloads/libpayload/drivers/usb/ehci.c
index bda415f..0aa799d 100644
--- a/payloads/libpayload/drivers/usb/ehci.c
+++ b/payloads/libpayload/drivers/usb/ehci.c
@@ -873,7 +873,7 @@
 	return controller;
 }
 
-#ifdef CONFIG_LP_USB_PCI
+#if IS_ENABLED(CONFIG_LP_USB_PCI)
 hci_t *
 ehci_pci_init (pcidev_t addr)
 {