Do not insert twice for first filter

On the first call, the filter list is empty,
the element will be insert two times, just return after the first insert.

Tested:
Check the filter callback functions, there is no duplicated call;

Signed-off-by: Yong Li <yong.b.li@linux.intel.com>
Change-Id: I4e4d5147b5c0466b651700f79afcb34940e6f48a
1 file changed