meta-nuvoton: npcm8xx: remove redundant append config

This append config already include at linux-nuvoton.inc.
No need to add this append here, thus remove it.

Tested:
Build pass and device boot up successfully.

Signed-off-by: Tim Lee <timlee660101@gmail.com>
Change-Id: Ifb72c9eb2df095c48292c6acc304e8a8a072fd03
diff --git a/meta-nuvoton/conf/machine/include/npcm8xx.inc b/meta-nuvoton/conf/machine/include/npcm8xx.inc
index 96fed00..1516966 100644
--- a/meta-nuvoton/conf/machine/include/npcm8xx.inc
+++ b/meta-nuvoton/conf/machine/include/npcm8xx.inc
@@ -43,8 +43,6 @@
 
 require conf/machine/include/arm/armv8a/tune-cortexa35.inc
 
-UBOOT_MKIMAGE:append:npcm8xx = " -E -B 8"
-
 COMPATIBLE_MACHINE:npcm8xx = "npcm8xx"
 TFA_PLATFORM = "npcm845x"