[stable] nospec: Kill array_index_nospec_mask_check()

[Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx>]

Based on the commit message, I think this needs to be backported to
stable branches:

commit 1d91c1d2c80cb70e2e553845e278b87a960c04da
Author: Dan Williams <dan.j.williams@xxxxxxxxx>
Date:   Fri Feb 16 13:20:42 2018 -0800

    nospec: Kill array_index_nospec_mask_check()

Is that right?

Ben.

-- 
Ben Hutchings
Software Developer, Codethink Ltd.