clocksource/drivers/qcom: Add missing iounmap() on errors in msm_dt_timer_init()

Add the missing iounmap() when clock frequency fails to get read by the
of_property_read_u32() call, or if the call to msm_timer_init() fails.

Fixes: 6e332163 ("ARM: msm: Add DT support to msm_timer")
Signed-off-by: Ankit Agrawal <agrawal.ag.ankit@gmail.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20240713095713.GA430091@bnew-VirtualBox


Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>