clk: samsung: exynos850: Implement CMU_APM domain

clk: samsung: exynos850: Implement CMU_APM domain

CMU_APM clock domain provides clocks for APM IP-core (Active Power
Management). According to Exynos850 TRM, CMU_APM generates I3C, Mailbox,
Speedy, Timer, WDT, RTC and PMU clocks for BLK_ALIVE.

This patch adds next clocks:
  - bus clocks in CMU_TOP needed for CMU_APM
  - all internal CMU_APM clocks
  - leaf clocks for I3C, Speedy and RTC IP-cores
  - bus clocks for CMU_CMGP and CMU_CHUB

CMU_APM doesn't belong to Power Domains, but platform driver is used for
its registration to keep its bus clock always running. Otherwise rtc-s3c
driver disables that clock and system freezes.

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
Link: https://lore.kernel.org/r/20211121232741.6967-3-semen.protsenko@linaro.org