Cortex-Axx: Unconditionally apply CPU reset operations

In the Cortex-A35/A53/A57 CPUs library code, some of the CPU specific
reset operations are skipped if they have already been applied in a
previous invocation of the reset handler. This precaution is not
required, as all these operations can be reapplied safely.

This patch removes the unneeded test-before-set instructions in
the reset handler for these CPUs.

Change-Id: Ib175952c814dc51f1b5125f76ed6c06a22b95167