ARM: shmobile: defconfig: Refresh for v5.1-rc1

Update the defconfig for Renesas ARM boards:
  - Move CMA-related config options (moved in commit ddb26d8e
    ("dma-mapping: move CONFIG_DMA_CMA to kernel/dma/Kconfig"),
  - Drop CONFIG_DRM_RCAR_LVDS=y (auto-enabled since commit
    02f2b300 ("drm: rcar-du: lvds: Add API to enable/disable
    clock output")),
  - Drop CONFIG_SND_SIMPLE_SCU_CARD=y (removed in commit
    c8ed6aca ("ASoC: simple-scu-card: remove simple-scu-card")).

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>