drm/amdgpu: add check to avoid array bound issue

Sub_block_index can be passed from user level, so
add one check before accessing the array first to
prevent array index out of bound problem.
Signed-off-by: Guchun Chen <guchun.chen@amd.com>
Reviewed-by: Tao Zhou <tao.zhou1@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c

@@ -5978,6 +5978,9 @@ static int gfx_v9_0_ras_error_inject(struct amdgpu_device *adev,
 	if (adev->asic_type != CHIP_VEGA20)
 		return -EINVAL;
 
+	if (info->head.sub_block_index >= ARRAY_SIZE(ras_gfx_subblocks))
+		return -EINVAL;
+
 	if (!ras_gfx_subblocks[info->head.sub_block_index].name)
 		return -EPERM;