st/va: fix memory leak on error in vlVaCreateSurfaces2
st/va: fix memory leak on error in vlVaCreateSurfaces2

Found by coverity: CID #1337953

Signed-off-by: Julien Isorce <2904e845d63d102574cbb95a4bcdefac0a5d7af0@samsung.com>
Reviewed-by: Christian König <c7ea837d7a46effe4232b086213468b8b31643bf@amd.com>
Reviewed-by: Emil Velikov <4c996f2f093ddd0585a556460b4cc3ba555546ef@gmail.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler