contrib: Fix some code style problems, ERROR: "foo * bar" should be "foo *bar"

I am reading contrib related code and found some style problems while
check the code using checkpatch.pl. This commit fixs the issue below:
ERROR: "foo * bar" should be "foo *bar"

Signed-off-by: zhouyang <zhouyang789@huawei.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210118031004.1662363-3-zhouyang789@huawei.com>
Message-Id: <20210213130325.14781-6-alex.bennee@linaro.org>

contrib/plugins/howvec.c

@@ -235,7 +235,7 @@ static void vcpu_insn_exec_before(unsigned int cpu_index, void *udata)
     (*count)++;
 }
 
-static uint64_t * find_counter(struct qemu_plugin_insn *insn)
+static uint64_t *find_counter(struct qemu_plugin_insn *insn)
 {
     int i;
     uint64_t *cnt = NULL;