display: modified SDL_SetVideoMode flag

display: modified SDL_SetVideoMode flag

Use SDL_SWSURFACE if you plan on doing per-pixel manipulations,
or blit surfaces with alpha channels, and require a high framerate.
When you use hardware surfaces, SDL copies the surfaces from video
memory to system memory when you lock them, and back when you unlock
them. This can cause a major performance hit.
 Be aware that you may request a hardware surface, but receive a
software surface because the video driver doesn't support hardware
surface. Many platforms can only provide a hardware surface when
using SDL_FULLSCREEN. The SDL_HWSURFACE flag is best used when
the surfaces you'll be blitting can also be stored in video memory.

Change-Id: I07484f931ac2956bb386234a0524066ee70cce1f
Signed-off-by: GiWoong Kim <giwoong.kim@samsung.com>