On exynos5 platforms the Arm Generic timer is available and is used for
MCS, but the mct.h is still used as the mct device needs to be
configured to implement the Arm Generic timer. mct.h is a common header
for register definitions while exynos4412-mct.h is used for implementing
timer functions on the exynos4 where the mct doesn't support being the
Arm generic timer.
Also remove misplaced initGenericTimer() declaration.
- use gpt, so we can have overflow and compare interrupts at the same
time (epit only allows compare)
- set the gpt to use the ipg_highfreq timer, as the standard ipg is too
low and breaks the timer calculations
Update the generic timer to implement the MCS kernels tickless timer
driver API and update all platforms that use the arm generic timers:
- bcm2837
- exynos5
- hikey
- imx7
- odroidc2
- tk1
- tx1
- tx2
- zynq7000
Also move the generic timer constants to machine.h to avoid a circular
dependency.
