encoder_base.cpp: check libva version before some declaration
encoder_base.cpp: check libva version before some declaration

add VA_CHECK_VERSION to judge whether to declare some variable
with this patch we can fix issue#397

Signed-off-by: Yizhou.Wei <e10eb354b8461e26a1293d73340e68f91dcc7a55@intel.com>

yizhouwei/libyami,YuJiankang/libyami,uartie/libyami,dspmeng/libyami,seanvk/libyami,zhaobob/libyami,dspmeng/libyami,stripes416/libyami,01org/libyami,lizhong1008/libyami,lizhong1008/libyami,lizhong1008/libyami,stripes416/libyami,dspmeng/libyami,uartie/libyami,stripes416/libyami,yizhouwei/libyami,YuJiankang/libyami,zhaobob/libyami,seanvk/libyami,uartie/libyami,seanvk/libyami,YuJiankang/libyami,zhaobob/libyami,01org/libyami,yizhouwei/libyami,01org/libyami