i965/meta: initialize values to avoid random behaviour on error path
i965/meta: initialize values to avoid random behaviour on error path

if brw_meta_stencil_blit() errored at wrong place 'target' would
be uninitialized and cause random behaviour on leaving the funtion.

Signed-off-by: Juha-Pekka Heikkila <cab67866509becb852d2a4e6f7e5924ad04fb975@gmail.com>
Reviewed-by: Eduardo Lima Mitev <86e6f0c9eba14994f25948ad50c226b324e9fa92@igalia.com>
Reviewed-by: Chad Versace <a557f7f75bf28dc19ac99107f5cc7cd6b3fbdb1a@intel.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler