arm64: cpufeature: Add missing .field_width for GIC system registers

mainline inclusion
from mainline-v5.18-rc1
commit b8fc7801
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8E73O
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b8fc780137b4b2d7b84d75488b429fd882e0dd3b



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This was missed when making specification of a field standard.

Fixes: 0a2eec83 ("arm64: cpufeature: Always specify and use a field width for capabilities")
Reported-by: Qian Cai <quic_qiancai@quicinc.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220302134225.159217-1-broonie@kernel.org


Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Wang ShaoBo <bobo.shaobowang@huawei.com>