pinctrl: sh-pfc: r8a7794: Add can_clk function

This patch adds can_clk function to r8a7745/r8a7794 which is cleaner,
and allows for independent configuration.
We keep the can_clk* pins definitions from within can0_groups and
can1_groups for uniformity and backwards compatibility.
Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: Ramesh Shanmugasundaram <ramesh.shanmugasundaram@bp.renesas.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

drivers/pinctrl/sh-pfc/pfc-r8a7794.c

@@ -3858,6 +3858,10 @@ static const char * const can0_groups[] = {
 	"can0_data_b",
 	"can0_data_c",
 	"can0_data_d",
+	/*
+	 * Retained for backwards compatibility, use can_clk_groups in new
+	 * designs.
+	 */
 	"can_clk",
 	"can_clk_b",
 	"can_clk_c",
@@ -3869,6 +3873,21 @@ static const char * const can1_groups[] = {
 	"can1_data_b",
 	"can1_data_c",
 	"can1_data_d",
+	/*
+	 * Retained for backwards compatibility, use can_clk_groups in new
+	 * designs.
+	 */
+	"can_clk",
+	"can_clk_b",
+	"can_clk_c",
+	"can_clk_d",
+};
+
+/*
+ * can_clk_groups allows for independent configuration, use can_clk function
+ * in new designs.
+ */
+static const char * const can_clk_groups[] = {
 	"can_clk",
 	"can_clk_b",
 	"can_clk_c",
@@ -4248,6 +4267,7 @@ static const struct sh_pfc_function pinmux_functions[] = {
 	SH_PFC_FUNCTION(avb),
 	SH_PFC_FUNCTION(can0),
 	SH_PFC_FUNCTION(can1),
+	SH_PFC_FUNCTION(can_clk),
 	SH_PFC_FUNCTION(du0),
 	SH_PFC_FUNCTION(du1),
 	SH_PFC_FUNCTION(eth),