arm64: defconfig: Default updates for genericarmv8

Due to changes in Kconfig default options, genericarmv8 is out of sync.
Sync genericarmv8 defconfig to the latest code.

Change-Id: I15d753b9d9429ac623fd7b7e7eaa936b5ed2a8b1
Signed-off-by: Pavankumar Kondeti <quic_pkondeti@quicinc.com>