arm64: Update default configuration

arm64: Update default configuration

Enable a couple of drivers that are used on Jetson TX1:

  * GPIO_PCA953X, GPIO_PCA953X_IRQ: Two instances of this I2C GPIO
    expander are used on Jetson TX1 to expand the number of usable GPIOs
    on the I/O board. Enable the driver for this expander along with IRQ
    support.

  * MFD_MAX77620, REGULATOR_MAX77620, PINCTRL_MAX77620, GPIO_MAX77620,
    RTC_DRV_MAX77686: Enable support for the PMIC and various of its
    components found on the Jetson TX1 processor module (p2180).

  * RTC_DRV_TEGRA: This RTC is usually not hooked up to a battery on
    boards, but it can be useful as a wakeup source from suspend to RAM.

  * REGULATOR_PWM: The GPU is supplied by a regulator controlled via one
    of the Tegra's PWM channels.

  * DRM, DRM_NOUVEAU, DRM_TEGRA, DRM_PANEL_SIMPLE: Enable support for an
    optional DSI panel on Jetson TX1 as well as the GPU.

  * BACKLIGHT_GENERIC, BACKLIGHT_LP855X: The backlight on Jetson TX1, if
    shipped with a display module, is driver by an LP8557.

  * PHY_TEGRA_XUSB, USB_XHCI_TEGRA: Enable support for XUSB (USB 3.0) on
    Jetson TX1.

  * PWM, PWM_TEGRA: One of the PWM channels is used to control the
    voltage supplied to the GPU.

  * NFS_V4_1, NFS_V4_2: Support these newer versions of the NFS protocol
    to increase compatibility with distributions.

  * MFD_CROS_EC, MFD_CROS_EC_I2C and I2C_CROS_EC_TUNNEL: Used to enable
    the ChromeOS Embedded Controller and the I2C tunnel that allows the
    EC to function as an I2C bridge.

  * BATTERY_BQ27XXX: Support the battery charger and monitor found on
    the Google Pixel C.

Signed-off-by: Thierry Reding <treding@nvidia.com>