arm64: defconfig: cleanup config options

arm64: defconfig: drop unused POWER_AVS option
Commit 785b5bb4 ("PM: AVS: Drop the avs directory and the
corresponding Kconfig") moved AVS code to SOC-specific folders, and
removed corresponding Kconfig from drivers/power, leaving original
POWER_AVS config option enabled in some defconfigs.
Remove the options, which have no references in the tree anymore.

arm64: defconfig: set CONFIG_USB_CONN_GPIO=y
Since 10a7b37b ("arm64: Update default configuration") PHY_TEGRA_XUSB
is set to y. That option needs USB_CONN_GPIO to also be y not m, so
set USB_CONN_GPIO explicitly to y to reflect reality.

arm64: defconfig: remove obsolete CONFIG_ARCH_AGILEX and CONFIG_ARCH_N5X
These config options were removed in 4a9a1a56 ("arm64: socfpga: merge
Agilex and N5X into ARCH_INTEL_SOCFPGA"), so remove them from the
defconfig.

arm64: defconfig: don't set CONFIG_ACPI_APEI_PCIEAER
Since 8c8ff55b

 ("PCI/AER: Don't select CONFIG_PCIEAER by default"), PCIe
Advanced Error Reporting isn't enabled by default.. As this means just
enabling CONFIG_CPI_APEI_PCIEAR does not have an effect, remove it from
the defconfig for clarity.

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>