Revert "Merge patch series "pxe: Allow extlinux booting without CMDLINE enabled""

As reported by Jonas Karlman this series breaks booting on some AArch64
platforms with common use cases. For now the best path forward is to
revert the series.

This reverts commit 777c28460947371ada40868dc994dfe8537d7115, reversing
changes made to ab3453e7b12daef47b9e91da2a2a3d48615dc6fc.

Link: https://lore.kernel.org/u-boot/50dfa3d6-a1ca-4492-a3fc-8d8c56b40b43@kwiboo.se/
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/xtensa/lib/Makefile b/arch/xtensa/lib/Makefile
index bb9157f..ad4fe32 100644
--- a/arch/xtensa/lib/Makefile
+++ b/arch/xtensa/lib/Makefile
@@ -3,6 +3,6 @@
 # (C) Copyright 2007 - 2013 Tensilica Inc.
 # (C) Copyright 2014 - 2016 Cadence Design Systems Inc.
 
-obj-$(CONFIG_BOOTM) += bootm.o
+obj-$(CONFIG_CMD_BOOTM) += bootm.o
 
 obj-y	+= cache.o misc.o relocate.o time.o