ANDROID: GKI: remove CONFIG_ARM_CPUIDLE=y

In commit 51280aca ("cpuidle: cpuidle-arm: remove arm64 support")
the generic ARM cpuidle option is removed as it is now properly handled
by the PSCI cpuidle code.  Remove this config option from the
gki_defconfig to resolve the build error caused by this removal.

Cc: Will Deacon <willdeacon@google.com>
Fixes: 51280aca ("cpuidle: cpuidle-arm: remove arm64 support")
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I92f5c31b27c25b31373ab7c9bb91ff84900d067b