arm64/sve: Track vector lengths for tasks in an array

mainline inclusion
from mainline-v5.16-rc1
commit 5838a155
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=5838a155798479e3fe7e1482a31f0db657d5bbdd



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As for SVE we will track a per task SME vector length for tasks. Convert
the existing storage for the vector length into an array and update
fpsimd_flush_task() to initialise this in a function.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20211019172247.3045838-10-broonie@kernel.org


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