cbfstool: Fix LzmaEnc.c and build with -Wshadow

LzmaEnc.c was full of shadow definitions. Luckily, shadow definitions
were not used after the scope in which they were redefined, so it is
possible to just remove them.

Tested by successfully booting qemu i440fx to grub2 payload.

Change-Id: I01d44db59882114ffe64434b655b931f3beec8e2
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Reviewed-on: http://review.coreboot.org/5082
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

util/cbfstool/Makefile

@@ -6,8 +6,7 @@ CFLAGS += -D_7ZIP_ST
 CFLAGS += -Wall -Wundef -Wstrict-prototypes -Wmissing-prototypes
 CFLAGS += -Wwrite-strings -Wredundant-decls -Wno-trigraphs
 CFLAGS += -Wstrict-aliasing -Werror
-# You're going to have to fix the LzmaEnc.c first -- it's horrible.
-# CFLAGS += -Wshadow
+CFLAGS += -Wshadow
 LDFLAGS += -g
 
 BINARY:=$(obj)/cbfstool