mkimage: fixup CONFIG_FIT_EXTERNAL_OFFSET

The last parameter is expected to be the imagefile.  Since -E is a
flag having the output name before -p will make mkimage ignore the
external offset option.
Signed-off-by: NPatrick Wildt <patrick@blueri.se>

Makefile

@@ -893,7 +893,7 @@ cmd_mkimage = $(objtree)/tools/mkimage $(MKIMAGEFLAGS_$(@F)) -d $< $@ \
 	>$(MKIMAGEOUTPUT) $(if $(KBUILD_VERBOSE:0=), && cat $(MKIMAGEOUTPUT))
 
 quiet_cmd_mkfitimage = MKIMAGE $@
-cmd_mkfitimage = $(objtree)/tools/mkimage $(MKIMAGEFLAGS_$(@F)) -f $(U_BOOT_ITS) -E $@ -p $(CONFIG_FIT_EXTERNAL_OFFSET)\
+cmd_mkfitimage = $(objtree)/tools/mkimage $(MKIMAGEFLAGS_$(@F)) -f $(U_BOOT_ITS) -E -p $(CONFIG_FIT_EXTERNAL_OFFSET) $@\
 	>$(MKIMAGEOUTPUT) $(if $(KBUILD_VERBOSE:0=), && cat $(MKIMAGEOUTPUT))
 
 quiet_cmd_cat = CAT     $@