drm/radeon/evergreen: Add comment for 'evergreen_page_flip()'s 'async' param

Fixes the following W=1 kernel build warning(s):

 drivers/gpu/drm/radeon/evergreen.c: In function ‘evergreen_gpu_init’:
 drivers/gpu/drm/radeon/evergreen.c:1419: warning: Function parameter or member 'async' not described in 'evergreen_page_flip'

Cc: Alex Deucher <[email protected]>
Cc: "Christian König" <[email protected]>
Cc: David Airlie <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Lee Jones <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>

0 files changed, 0 insertions, 0 deletions