clk: renesas: Provide Kconfig symbols for CPG/MSSR and CPG/MSTP support

Currently the decision whether to build the renesas-cpg-mssr and
clk-mstp drivers is handled by Makefile logic.  However, the rcar-sysc
driver will need to know whether CPG/MSSR and/or CPG/MSTP support are
available or not.

To avoid having to duplicate this logic, move it to Kconfig. Provide
non-visible CLK_RENESAS_CPG_MSSR and CLK_RENESAS_CPG_MSTP Kconfig
symbols, which can be used by both Makefiles and C code.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
diff --git a/drivers/clk/renesas/Makefile b/drivers/clk/renesas/Makefile
index 7e2579b..ead8bb8 100644
--- a/drivers/clk/renesas/Makefile
+++ b/drivers/clk/renesas/Makefile
@@ -1,13 +1,15 @@
 obj-$(CONFIG_ARCH_EMEV2)		+= clk-emev2.o
-obj-$(CONFIG_ARCH_R7S72100)		+= clk-rz.o clk-mstp.o
-obj-$(CONFIG_ARCH_R8A73A4)		+= clk-r8a73a4.o clk-mstp.o clk-div6.o
-obj-$(CONFIG_ARCH_R8A7740)		+= clk-r8a7740.o clk-mstp.o clk-div6.o
-obj-$(CONFIG_ARCH_R8A7778)		+= clk-r8a7778.o clk-mstp.o
-obj-$(CONFIG_ARCH_R8A7779)		+= clk-r8a7779.o clk-mstp.o
-obj-$(CONFIG_ARCH_R8A7790)		+= clk-rcar-gen2.o clk-mstp.o clk-div6.o
-obj-$(CONFIG_ARCH_R8A7791)		+= clk-rcar-gen2.o clk-mstp.o clk-div6.o
-obj-$(CONFIG_ARCH_R8A7793)		+= clk-rcar-gen2.o clk-mstp.o clk-div6.o
-obj-$(CONFIG_ARCH_R8A7794)		+= clk-rcar-gen2.o clk-mstp.o clk-div6.o
-obj-$(CONFIG_ARCH_R8A7795)		+= renesas-cpg-mssr.o \
-					   r8a7795-cpg-mssr.o clk-div6.o
-obj-$(CONFIG_ARCH_SH73A0)		+= clk-sh73a0.o clk-mstp.o clk-div6.o
+obj-$(CONFIG_ARCH_R7S72100)		+= clk-rz.o
+obj-$(CONFIG_ARCH_R8A73A4)		+= clk-r8a73a4.o clk-div6.o
+obj-$(CONFIG_ARCH_R8A7740)		+= clk-r8a7740.o clk-div6.o
+obj-$(CONFIG_ARCH_R8A7778)		+= clk-r8a7778.o
+obj-$(CONFIG_ARCH_R8A7779)		+= clk-r8a7779.o
+obj-$(CONFIG_ARCH_R8A7790)		+= clk-rcar-gen2.o clk-div6.o
+obj-$(CONFIG_ARCH_R8A7791)		+= clk-rcar-gen2.o clk-div6.o
+obj-$(CONFIG_ARCH_R8A7793)		+= clk-rcar-gen2.o clk-div6.o
+obj-$(CONFIG_ARCH_R8A7794)		+= clk-rcar-gen2.o clk-div6.o
+obj-$(CONFIG_ARCH_R8A7795)		+= r8a7795-cpg-mssr.o
+obj-$(CONFIG_ARCH_SH73A0)		+= clk-sh73a0.o clk-div6.o
+
+obj-$(CONFIG_CLK_RENESAS_CPG_MSSR)	+= renesas-cpg-mssr.o clk-div6.o
+obj-$(CONFIG_CLK_RENESAS_CPG_MSTP)	+= clk-mstp.o