blkzone: remove unnecessary initializations

C compiler is smart enough to follow C standards

 C11: 6.7.8 Initialization

 All subobjects that are not initialized explicitly shall be
 initialized implicitly the same as objects that have static storage
 duration.

Signed-off-by: Karel Zak <kzak@redhat.com>

sys-utils/blkzone.c

@@ -379,10 +379,7 @@ int main(int argc, char **argv)
 {
 	int c;
 	struct blkzone_control ctl = {
-		.devname = NULL,
-		.offset = 0,
-		.count = 0,
-		.length = 0
+		.devname = NULL
 	};
 
 	static const struct option longopts[] = {