r600g: check NULL return from r600_aligned_buffer_create
r600g: check NULL return from r600_aligned_buffer_create

Signed-off-by: Julien Isorce <341b42cefd783c11d105e1f99b43728d48a9b5d2@oblong.com>
Reviewed-by: Marek Olšák <8c7344a1abdb103e79ecfd488098373070c3c70e@amd.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler