ARM: Fix "white screen" problem

ARM: Fix "white screen" problem

There was a problem with redrawing of the emulator screen by some
window managers. This problem appears only on ARM emulator with
exynos4210 FIMD usage. Also, this problem doesn't appear when SDL
window isn't integrated into emulator skin with SWT.EMBEDDED flag.

Normally (without skin) the host window system repairs window when
receives the paint event. But in our case this events is caught by
SWT library and window system doesn't do that. We should do that by
ourself. maru_vga update the window continuously. But exynos4210 FIMD
calls update function only when there are changes on the screen. So
sometimes we can see the "white screen" until click in the screen.

If we fix that in the FIMD, we will get overhead. SDL more suuitable
for that.