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>

payloads/libpayload/arch/x86/sysinfo.c

@@ -38,7 +38,7 @@
  */
 struct sysinfo_t lib_sysinfo = {
 	.cpu_khz = 200,
-#ifdef CONFIG_LP_SERIAL_CONSOLE
+#if IS_ENABLED(CONFIG_LP_SERIAL_CONSOLE)
 	.ser_ioport = CONFIG_LP_SERIAL_IOBASE,
 #else
 	.ser_ioport = 0x3f8,
@@ -52,7 +52,7 @@ int lib_get_sysinfo(void)
 	/* Get the CPU speed (for delays). */
 	lib_sysinfo.cpu_khz = get_cpu_speed();
 
-#ifdef CONFIG_LP_MULTIBOOT
+#if IS_ENABLED(CONFIG_LP_MULTIBOOT)
 	/* Get the information from the multiboot tables,
 	 * if they exist */
 	get_multiboot_info(&lib_sysinfo);