drm: ttm sparse fixes.

Correct allocation flags type and function prototype for ANSI C compliance.

[airlied: whitespace fixed]

Signed-off-by: Daniel J Blueman <daniel.blueman@gmail.com>
Reviewed-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>