arm64: defconfig: Enable CONFIG_UNUSED_KSYMS_WHITELIST_ONLY

Enable CONFIG_UNUSED_KSYMS_WHITELIST_ONLY for Lahaina's GKI
platform to detect if an update to the whitelist is needed.

Also update the ABI snapshot as many of the function will be
seen as deleted.

Change-Id: I5e96899dd69462e1a32ae7b512be8d4de9ea1b2d
Signed-off-by: Raghavendra Rao Ananta <rananta@codeaurora.org>