v4l2dec: Remove build result from source folder [1/2]

PD#SWPL-151598

Problem:
Remove build result from git folder to build result folder

Solution:
add output folder from bb to Makefile,
add .gitignore file

Verify:
local

Signed-off-by: guoping.li <guoping.li@amlogic.com>
Change-Id: I6fa67a8776842de7bf4a745a642edccf6f4b28a6
3 files changed