Fixup AArch32 errata printing framework

The AArch32 assembly implementation of `print_errata_status` did not save
a register which was getting clobbered by a `get_cpu_ops_ptr`. This
patch fixes that.

Change-Id: Id0711e46b7c685a18a10328d4b513e952a5d860b
Signed-off-by: Soby Mathew <soby.mathew@arm.com>