clk: renesas: cpg-mssr: Use always-on governor for Clock Domain

As a pure Clock Domain does not have the concept of powering the domain
itself, the CPG/MSTP driver does not provide power_off() and power_on()
callbacks.
However, the genpd core may still perform a dummy power down, causing
/sys/kernel/debug/pm_genpd/pm_genpd_summary to report the domain's
status being "off-0".

Use the always-on governor to make sure the domain is never powered
down, and always shows up as "on" in pm_genpd_summary.

Signed-off-by: Geert Uytterhoeven <[e-mail]>
Reviewed-by: Laurent Pinchart <[e-mail]>
Reviewed-by: Ulf Hansson <[e-mail]>

drivers/clk/renesas/renesas-cpg-mssr.c

···
 	genpd->flags = GENPD_FLAG_PM_CLK;
 	genpd->attach_dev = cpg_mssr_attach_dev;
 	genpd->detach_dev = cpg_mssr_detach_dev;
-	pm_genpd_init(genpd, &simple_qos_governor, false);
+	pm_genpd_init(genpd, &pm_domain_always_on_gov, false);
 	cpg_mssr_clk_domain = pd;
 
 	of_genpd_add_provider_simple(np, genpd);