arm64: Relax GIC version check during early boot

arm64: Relax GIC version check during early boot

[ Upstream commit 74698f6971f25d045301139413578865fc2bd8f9 ]

Updates to the GIC architecture allow ID_AA64PFR0_EL1.GIC to have
values other than 0 or 1. At the moment, Linux is quite strict in the
way it handles this field at early boot stage (cpufeature is fine) and
will refuse to use the system register CPU interface if it doesn't
find the value 1.

Fixes: 021f653791ad17e03f98aaa7fb933816ae16f161 ("irqchip: gic-v3: Initial support for GICv3")
Reported-by: Chase Conklin <Chase.Conklin@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>