arm: Do not define TLBTR in PMSA systems

arm: Do not define TLBTR in PMSA systems

If doing a PMSA (MPU) system do not define the VMSA specific TLBTR CP.
The def is done separately from VMSA registers group as it is affected
by both the OMAP/STRONGARM RW errata and the MIDR backgrounding.

Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Message-id: b03fea3840207edf633f5c9189400c3dd6a28d14.1434066412.git.peter.crosthwaite@xilinx.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>