[video360] Fix 2 bugs

[video360] Fix 2 bugs

1. Remove invalid buffer referencing
 : It seems that the additional buffer referencing is needed because of bug in gstvideofilter,
   But, it's fixed and now, this buffer referencing code causes buffer handling error after that.
   So, the buffer referencing code should be removed.

2. Correct passthrough function
 : Previously, the new output buffer is allocated and it's pushed without any change, so it caused black screen.
   This patch changes the logic when passthrough is true like below.
   - Just assign input buffer as output buffer without new allocation.

[Version] 1.16.2-2
[Profile] Common
[Issue Type] Bug fix

Change-Id: Ida2f2926ea4f2e8374f12acfbc80b587217bebbf
Signed-off-by: Jeongmo Yang <jm80.yang@samsung.com>