drm/exynos: fimd and ipp are broken on multiplatform

While the exynos DRM support in principle can work on
multiplatform, the FIMD and IPP sections of it both
include the plat/map-base.h header file, which is
not available on multiplatform. Rather than disabling
the entire driver, we can just conditionally build
these two parts.

Without this patch, building allyesconfig results in:

drivers/gpu/drm/exynos/exynos_drm_fimc.c:19:27: fatal error: plat/map-base.h: No such file or directory
drivers/gpu/drm/exynos/exynos_drm_ipp.c:20:27: fatal error: plat/map-base.h: No such file or directory

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>