clk: shmobile: r8a7778: Add CPG/MSTP Clock Domain support

Add Clock Domain support to the R-Car M1A Clock Pulse Generator (CPG)
driver using the generic PM Domain.  This allows to power-manage the
module clocks of SoC devices that are part of the CPG/MSTP Clock Domain
using Runtime PM, or for system suspend/resume.

SoC devices that are part of the CPG/MSTP Clock Domain and can be
power-managed through an MSTP clock should be tagged in DT with a proper
"power-domains" property.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Stephen Boyd <sboyd@codeaurora.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
diff --git a/drivers/clk/shmobile/clk-r8a7778.c b/drivers/clk/shmobile/clk-r8a7778.c
index cb33b57..fa45684 100644
--- a/drivers/clk/shmobile/clk-r8a7778.c
+++ b/drivers/clk/shmobile/clk-r8a7778.c
@@ -124,6 +124,8 @@
 	}
 
 	of_clk_add_provider(np, of_clk_src_onecell_get, &cpg->data);
+
+	cpg_mstp_add_clk_domain(np);
 }
 
 CLK_OF_DECLARE(r8a7778_cpg_clks, "renesas,r8a7778-cpg-clocks",