ARM: exynos_defconfig: restore framebuffer support

ARM: exynos_defconfig: restore framebuffer support

Commit 6b2c04b84121 ("drm: Avoid circular dependencies for CONFIG_FB")
changed the Kconfig dependencies, so COFNIG_FB is no longer selected in
defconfigs. Restore support for it in exynos_defconfig, because most
Exynos platforms had graphical console running on framebuffer device
emulated on the Exynos DRM drivers.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20210611100204.6240-1-m.szyprowski@samsung.com
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>