ifwitool: Add new tool for managing IFWI images

- Supports following operations:
 1. add raw/dir sub-partition
 2. extract raw/dir sub-partition
 3. print info
 4. delete raw sub-partition
 5. replace raw/dir sub-partition

Change-Id: I683a0ab13cc50eb60eecca34db4a8ffefc8dccbd
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/14896
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

util/cbfstool/Makefile

@@ -10,6 +10,7 @@ OBJCOPY ?= objcopy
 all: $(objutil)/cbfstool/cbfstool \
 	$(objutil)/cbfstool/fmaptool \
 	$(objutil)/cbfstool/rmodtool \
+	$(objutil)/cbfstool/ifwitool \
 
 .PHONY: clean
 clean:
@@ -17,6 +18,7 @@ clean:
 	$(RM) $(objutil)/cbfstool/cbfstool $(cbfsobj)
 	$(RM) $(objutil)/cbfstool/fmaptool $(fmapobj)
 	$(RM) $(objutil)/cbfstool/rmodtool $(rmodobj)
+	$(RM) $(objutil)/cbfstool/ifwitool $(ifwiobj)
 
 linux_trampoline.c: linux_trampoline.S
 	rm -f linux_trampoline.c