clk: renesas: rcar-gen3: Parameterise Z and Z2 clock fixed divisor

Parameterise Z and Z2 clock fixed divisor to allow clocks with a fixed
divisor other than 2, the value used by all such clocks supported to date.

This is in preparation for supporting the Z2 clock on the R-Car E3
(r8a77990) SoC which has a fixed divisor of 4.

Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
[simon: squashed several patches; rewrote changelog; added r8a774a1 change]
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

drivers/clk/renesas/rcar-gen3-cpg.h

@@ -3,6 +3,7 @@
  * R-Car Gen3 Clock Pulse Generator
  *
  * Copyright (C) 2015-2018 Glider bvba
+ * Copyright (C) 2018 Renesas Electronics Corp.
  *
  */
 
@@ -51,6 +52,9 @@ enum rcar_gen3_clk_types {
 	DEF_BASE(_name, _id, CLK_TYPE_GEN3_RCKSEL,	\
 		 (_parent0) << 16 | (_parent1),	.div = (_div0) << 16 | (_div1))
 
+#define DEF_GEN3_Z(_name, _id, _type, _parent, _div)	\
+	DEF_BASE(_name, _id, _type, _parent, .div = _div)
+
 struct rcar_gen3_cpg_pll_config {
 	u8 extal_div;
 	u8 pll1_mult;