drm/msm/mdp5: Fix compilation warnings

Following compilation warnings were observed for these files:

  CC [M]  drivers/gpu/drm/msm/mdp/mdp5/mdp5_mdss.o
drivers/gpu/drm/msm/mdp/mdp5/mdp5_crtc.c: In function 'blend_setup':
drivers/gpu/drm/msm/mdp/mdp5/mdp5_crtc.c:223:7: warning: missing braces around initializer [-Wmissing-braces]
  enum mdp5_pipe stage[STAGE_MAX + 1][MAX_PIPE_STAGE] = { SSPP_NONE };
       ^
drivers/gpu/drm/msm/mdp/mdp5/mdp5_crtc.c:223:7: warning: (near initialization for 'stage[0]') [-Wmissing-braces]
drivers/gpu/drm/msm/mdp/mdp5/mdp5_crtc.c:224:7: warning: missing braces around initializer [-Wmissing-braces]
  enum mdp5_pipe r_stage[STAGE_MAX + 1][MAX_PIPE_STAGE] = { SSPP_NONE };
       ^
drivers/gpu/drm/msm/mdp/mdp5/mdp5_crtc.c:224:7: warning: (near initialization for 'r_stage[0]') [-Wmissing-braces]

drivers/gpu/drm/msm/mdp/mdp5/mdp5_plane.c: In function 'mdp5_plane_mode_set':
drivers/gpu/drm/msm/mdp/mdp5/mdp5_plane.c:892:9: warning: missing braces around initializer [-Wmissing-braces]
  struct phase_step step = { 0 };
         ^
drivers/gpu/drm/msm/mdp/mdp5/mdp5_plane.c:892:9: warning: (near initialization for 'step.x') [-Wmissing-braces]
drivers/gpu/drm/msm/mdp/mdp5/mdp5_plane.c:893:9: warning: missing braces around initializer [-Wmissing-braces]
  struct pixel_ext pe = { 0 };
         ^
drivers/gpu/drm/msm/mdp/mdp5/mdp5_plane.c:893:9: warning: (near initialization for 'pe.left') [-Wmissing-braces]

This happens because in the first case we were initializing a two
dimensional array with {0} and in the second case we were initializing a
struct containing two arrays with {0}.

Fix them by adding another pair of {}.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>