pinctrl: renesas: Add support for 1.8V/2.5V I/O voltage levels

Currently, the Renesas pin control driver supports pins that can switch
their I/O voltage levels between either 1.8V and 3.3V, or between 2.5V
and 3.3V.  However, some SoCs have pins that can switch between 1.8V and
2.5V.

Add support for this by replacing the separate SH_PFC_PIN_CFG_IO_VOLTAGE
capability and voltage level flags by a 2-bit field, to cover three
possible I/O voltage switching options.

Ported from Linux kernel commit by Geert Uytterhoeven:
b88e733ac517 ("pinctrl: renesas: Add support for 1.8V/2.5V I/O voltage levels")

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
diff --git a/drivers/pinctrl/renesas/sh_pfc.h b/drivers/pinctrl/renesas/sh_pfc.h
index bf40944..e6c2117 100644
--- a/drivers/pinctrl/renesas/sh_pfc.h
+++ b/drivers/pinctrl/renesas/sh_pfc.h
@@ -26,19 +26,13 @@
 #define SH_PFC_PIN_CFG_PULL_DOWN	(1 << 3)
 #define SH_PFC_PIN_CFG_PULL_UP_DOWN	(SH_PFC_PIN_CFG_PULL_UP | \
 					 SH_PFC_PIN_CFG_PULL_DOWN)
-#define SH_PFC_PIN_CFG_IO_VOLTAGE	(1 << 4)
-#define SH_PFC_PIN_CFG_DRIVE_STRENGTH	(1 << 5)
 
-#define SH_PFC_PIN_VOLTAGE_18_33	(0 << 6)
-#define SH_PFC_PIN_VOLTAGE_25_33	(1 << 6)
-#define SH_PFC_PIN_VOLTAGE_18_25	(2 << 6)
+#define SH_PFC_PIN_CFG_IO_VOLTAGE_MASK	GENMASK(5, 4)
+#define SH_PFC_PIN_CFG_IO_VOLTAGE_18_25	(1 << 4)
+#define SH_PFC_PIN_CFG_IO_VOLTAGE_18_33	(2 << 4)
+#define SH_PFC_PIN_CFG_IO_VOLTAGE_25_33	(3 << 4)
 
-#define SH_PFC_PIN_CFG_IO_VOLTAGE_18_33	(SH_PFC_PIN_CFG_IO_VOLTAGE | \
-					 SH_PFC_PIN_VOLTAGE_18_33)
-#define SH_PFC_PIN_CFG_IO_VOLTAGE_25_33	(SH_PFC_PIN_CFG_IO_VOLTAGE | \
-					 SH_PFC_PIN_VOLTAGE_25_33)
-#define SH_PFC_PIN_CFG_IO_VOLTAGE_18_25	(SH_PFC_PIN_CFG_IO_VOLTAGE | \
-					 SH_PFC_PIN_VOLTAGE_18_25)
+#define SH_PFC_PIN_CFG_DRIVE_STRENGTH	(1 << 6)
 
 #define SH_PFC_PIN_CFG_NO_GPIO		(1 << 31)