target-arm: Implement the generic timer

target-arm: Implement the generic timer

The ARMv7 architecture specifies a 'generic timer' which is implemented
via cp15 registers. Newer kernels will prefer to use this rather than
a devboard-level timer. Implement the generic timer for TCG; for KVM
we will already use the hardware's virtualized timer for this.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Tested-by: Laurent Desnogues <laurent.desnogues@gmail.com>
Message-id: 1376065080-26661-4-git-send-email-peter.maydell@linaro.org