ARM: shmobile: defconfig: Refresh for v5.18-rc1

Refresh the defconfig for Renesas ARM systems:
  - Move CONFIG_V4L_MEM2MEM_DRIVERS (moved in commit 256bf685
    ("media: platform: move platform menu dependencies to drivers")),
  - Move CONFIG_DEBUG_FS (moved in commit f9b3cd24
    ("Kconfig.debug: make DEBUG_INFO selectable from a choice")).

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/922ba60d81a71acfae5d88c1991d8c96bb2b3527.1649947421.git.geert+renesas@glider.be