Remove inapplicable 8064 errata workaround

msm: acpuclock-krait: Remove inapplicable 8064 errata workaround
The secondary MUX switching errata is worked around in the secure
warm-boot path, and does not require an in-kernel workaround.
For devices with older warm-boot code (without the workaround),
the removal of the kernel workaround is also safe. The errata
symptoms can only manifest themselves after an L2 power-collapse,
which can't occur until after all Krait CPUs have been brought
online at least once. Since the secondary MUX is only touched by
acpuclock when onlining CPUs for the first time, the MUX will
never be switched after L2 power-collapse.