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/configs/iot_devkit_defconfig b/configs/iot_devkit_defconfig
index d02a28a..c492005 100644
--- a/configs/iot_devkit_defconfig
+++ b/configs/iot_devkit_defconfig
@@ -14,12 +14,12 @@
 CONFIG_SYS_CLK_FREQ=16000000
 CONFIG_SYS_LOAD_ADDR=0x30000000
 CONFIG_LOCALVERSION="-iotdk-1.0"
-# CONFIG_BOOTM is not set
 # CONFIG_ARCH_FIXUP_FDT_MEMORY is not set
 CONFIG_SYS_CBSIZE=256
 CONFIG_SYS_PBSIZE=280
 CONFIG_SYS_PROMPT="IoTDK# "
 # CONFIG_CMD_BOOTD is not set
+# CONFIG_CMD_BOOTM is not set
 # CONFIG_CMD_ELF is not set
 # CONFIG_CMD_XIMG is not set
 # CONFIG_CMD_LOADB is not set