efi: app: Clean up defconfig

Move some #undef from efi-x86.h to efi-x86_defconfig as these are
already Kconfig options.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/efi-x86_defconfig b/configs/efi-x86_defconfig
index 943ef07..b4cbd5f 100644
--- a/configs/efi-x86_defconfig
+++ b/configs/efi-x86_defconfig
@@ -3,6 +3,7 @@
 CONFIG_DEFAULT_DEVICE_TREE="efi"
 CONFIG_TARGET_EFI=y
 # CONFIG_CMD_BOOTM is not set
+# CONFIG_CMD_IMLS is not set
 CONFIG_CMD_GPIO=y
 # CONFIG_CMD_NET is not set
 CONFIG_OF_CONTROL=y
@@ -13,6 +14,5 @@
 CONFIG_DEBUG_UART_BASE=0
 CONFIG_DEBUG_UART_CLOCK=0
 CONFIG_ICH_SPI=y
-# CONFIG_X86_SERIAL is not set
 CONFIG_TIMER=y
 CONFIG_EFI=y