Workaround for Neoverse N1 erratum 1262606

Workaround for Neoverse N1 erratum 1262606

Neoverse N1 erratum 1262606 is a Cat B erratum [1],
present in older revisions of the Neoverse N1 processor core.
The workaround is to set a bit in the implementation defined
CPUACTLR_EL1 system register, which delays instruction fetch after
branch misprediction.

[1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.pjdoc-466751330-10325/index.html

Change-Id: Idd980e9d5310232d38f0ce272862e1fb0f02ce9a
Signed-off-by: Lauren Wehrmeister <lauren.wehrmeister@arm.com>