target-arm: Add the pmceid0 and pmceid1 registers

target-arm: Add the pmceid0 and pmceid1 registers

Signed-off-by: Aaron Lindsay <alindsay@codeaurora.org>
Signed-off-by: Alistair Francis <alistair.francis@xilinx.com>
Tested-by: Nathan Rossi <nathan@nathanrossi.com>
Message-id: da0563119a9f56fd5fbdc26e7ed19a8a8457c5b9.1455060548.git.alistair.francis@xilinx.com
[PMM: Use 0 for PMCEID0 values for A15 and A57 since our PMU
 does not currently implement any events.]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>