exynos: font: buffer doesn't need special color initialization
exynos: font: use defaults properties for buffer bpp
exynos: font: use restrict for src/dst in put_glyph_rgba4444

This should help the compiler to generate better code for
memory access.
exynos: remove G2D safety zone

Extensive tests have shown that this is no longer necessary.
exynos: also use interpolate mode for menu blending
exynos: update TODO list
Merge pull request #864 from tobiasjakobi/fixes

exynos: cleanups and further improvements to font rendering