arm64: dts: s32g274-rd2: Enable the STM timers

arm64: dts: s32g274-rd2: Enable the STM timers

Enable the timers STM0 -> STM3 on the s32g274-rd2

The platform has 4 CPUs, and the Linux STM timer driver is
instantiated per CPU.  Enable 4 STM timers that can be used as
replacements for the ARM architected timers.  The remaining STM timers
are not useful to the Linux kernel and provide no benefit, so they are
left disabled.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Ghennadi Procopciuc <ghennadi.procopciuc@nxp.com>
Cc: Thomas Fossati <thomas.fossati@linaro.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>