mkimage -l is broken for images after gpimage

Because a gpimage cannot be detected, a false
GP header is printed instead of checking
for further image types.

Move gpimage as last to be linked, letting check
all other image types and printing a GP header just
in case no image is detected.

Signed-off-by: Stefano Babic <sbabic@denx.de>

tools/Makefile

@@ -76,8 +76,6 @@ dumpimage-mkimage-objs := aisimage.o \
 			lib/fdtdec.o \
 			fit_common.o \
 			fit_image.o \
-			gpimage.o \
-			gpimage-common.o \
 			common/image-fit.o \
 			image-host.o \
 			common/image.o \
@@ -100,6 +98,8 @@ dumpimage-mkimage-objs := aisimage.o \
 			zynqimage.o \
 			zynqmpimage.o \
 			$(LIBFDT_OBJS) \
+			gpimage.o \
+			gpimage-common.o \
 			$(RSA_OBJS-y)
 
 dumpimage-objs := $(dumpimage-mkimage-objs) dumpimage.o