ARM: config: ux500: Update U8500 defconfig

This updates the defconfig for the U8500 platform with
some of the changes from the v5.9 and v5.10 kernel
cycles:

- No need to select the schedutil cpufreq governor
  because it is the default now.
- Enable the CY8CTMA140 touchscreen as used on the
  Samsung Skomer GT-S7710.
- Enable the Samsung S6E63M0 DSI panel as used on
  the Samsung Golden GT-I8810.
- Enable the KTD253 backlight as used on the Samsung
  Skomer GT-S7710.
- Drop CONFIG_USB as we only use the gadget mode of
  the MUSB driver.
- Add selection of the CONFIG_LEDS_LP55XX_COMMON
  lest the LP5521 LEDs will not work.
- Move the config entry for CONFIG_DEBUG_FS.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Cc: Stephan Gerhold <stephan@gerhold.net>
Link: https://lore.kernel.org/r/20201105134510.1417639-1-linus.walleij@linaro.org'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>