hw/arm/imx8mp-evk: Fix guest time in KVM mode

hw/arm/imx8mp-evk: Fix guest time in KVM mode

The imx8mp DTB hardcodes the clock frequency of the system counter to 8MHz.
In KVM mode, the host CPU is used whose system counter runs at a different
frequency, resulting in the guest clock running slower or faster. Fix this
by not hardcoding the clock frequency which makes the Linux driver read
the real clock frequency from the register.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Bernhard Beschow <shentey@gmail.com>
Message-id: 20251101120130.236721-3-shentey@gmail.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>