dt-bindings: timer: Add NXP System Timer Module

dt-bindings: timer: Add NXP System Timer Module

Add the System Timer Module description found on the NXP s32 platform
and the compatible for the s32g2 variant.

Cc: Ghennadi Procopciuc <ghennadi.procopciuc@oss.nxp.com>
Cc: Thomas Fossati <thomas.fossati@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/r/20250417151623.121109-2-daniel.lezcano@linaro.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>