arm64/fpsimd: Fix typo in comment

Delete the redundant word 'in'.

Signed-off-by: Xiang wangx <wangxiang@cdjrlc.com>
Link: https://lore.kernel.org/r/20220610070543.59338-1-wangxiang@cdjrlc.com


Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>