arm64: Add cavium_erratum_23154_cpus missing sentinel

Qian Cai reported that playing with CPU hotplug resulted in a
out-of-bound access due to cavium_erratum_23154_cpus missing
a sentinel indicating the end of the array.

Add it in order to restore peace and harmony in the world
of broken HW.

Reported-by: Qian Cai <quic_qiancai@quicinc.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Fixes: 24a147bc ("irqchip/gic-v3: Workaround Marvell erratum 38545 when reading IAR")
Link: https://lore.kernel.org/r/YijmkXp1VG7e8lDx@qian
Cc: Linu Cherian <lcherian@marvell.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20220309180600.3990874-1-maz@kernel.org


Signed-off-by: Will Deacon <will@kernel.org>