clk: renesas: prepare for non R-Car clock drivers

Add new CONFIG_CLK_RCAR to control compilation of shared code for R-Car
clock drivers (renesas-cpg-mssr.c). Enable this for R-Car Gen2 and 3.

This is necessary so that CONFIG_CLK_RENESAS can be enabled, allowing
recursion into the drivers/clk/reneasas directory, without bringing in
the R-Car support code. The support code contains platform specific
access (TMU_BASE) which is not needed on other Renesas devices such as
RZ/N1.

Signed-off-by: Ralph Siemsen <ralph.siemsen@linaro.org>
Reviewed-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
diff --git a/drivers/clk/renesas/Kconfig b/drivers/clk/renesas/Kconfig
index 45671c6..bdb81a1 100644
--- a/drivers/clk/renesas/Kconfig
+++ b/drivers/clk/renesas/Kconfig
@@ -2,7 +2,12 @@
 	bool "Renesas clock drivers"
 	depends on CLK && ARCH_RMOBILE
 	help
-	  Enable support for clock present on Renesas RCar SoCs.
+	  Enable support for clock present on Renesas SoCs.
+
+config CLK_RCAR
+	bool "Renesas RCar clock driver support"
+	help
+	  Enable common code for clocks on Renesas RCar SoCs.
 
 config CLK_RCAR_CPG_LIB
 	bool "CPG/MSSR library functions"
@@ -11,6 +16,7 @@
 	bool "Renesas RCar Gen2 clock driver"
 	def_bool y if RCAR_32
 	depends on CLK_RENESAS
+	select CLK_RCAR
 	help
 	  Enable this to support the clocks on Renesas RCar Gen2 SoC.
 
@@ -48,6 +54,7 @@
 	bool "Renesas RCar Gen3 and Gen4 clock driver"
 	def_bool y if RCAR_64
 	depends on CLK_RENESAS
+	select CLK_RCAR
 	select CLK_RCAR_CPG_LIB
 	select DM_RESET
 	help
diff --git a/drivers/clk/renesas/Makefile b/drivers/clk/renesas/Makefile
index fe0391e..c95dee6 100644
--- a/drivers/clk/renesas/Makefile
+++ b/drivers/clk/renesas/Makefile
@@ -1,4 +1,4 @@
-obj-$(CONFIG_CLK_RENESAS) += renesas-cpg-mssr.o
+obj-$(CONFIG_CLK_RCAR) += renesas-cpg-mssr.o
 obj-$(CONFIG_CLK_RCAR_CPG_LIB) += rcar-cpg-lib.o
 obj-$(CONFIG_CLK_RCAR_GEN2) += clk-rcar-gen2.o
 obj-$(CONFIG_CLK_R8A774A1) += r8a774a1-cpg-mssr.o