For a shared timers, the mct_init_dt() should not initialize the clock
even with global comparator.  This is not an error, thus the function
should simply return 0, not 'ret'.

This also fixes smatch warning:

  drivers/clocksource/exynos_mct.c:635 mct_init_dt() warn: missing error code? 'ret'
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <error27@gmail.com>
Link: https://lore.kernel.org/r/202304021446.46XVKag0-lkp@intel.com/Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Reviewed-by: Alim Akhtar <alim.akhtar@samsung.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20230403094017.9556-1-krzysztof.kozlowski@linaro.org