tools: zstd: dont override ZSTD_LEGACY_SUPPORT

We dont really have a reason to deviate from the upstream default for
ZSTD_LEGACY_SUPPORT value of 5, as it will save a bit of space but
prevent decompressing data compressed with legacy ZSTD versions.

Signed-off-by: Robert Marko <robimarko@gmail.com>

tools/zstd/Makefile

@@ -21,7 +21,6 @@ HOST_CFLAGS += \
 	-DZSTDCLI_CLEVEL_MAX=20
 
 HOST_MAKE_FLAGS += \
-	ZSTD_LEGACY_SUPPORT=7 \
 	BACKTRACE=0 \
 	HAVE_THREAD=1 \
 	HAVE_ZLIB=0 \