hwmon: (it87) Allow calling __superio_enter outside muxed region

Allow for superio_enter to be called without requesting the muxed memory
region, in particular for initialisation of the second chipset, which must
be put into configuration mode, but without an associated call to leave
configuration mode.
Signed-off-by: Frank Crawford <frank@crawford.emu.id.au>
Link: https://lore.kernel.org/r/20230104060926.619686-2-frank@crawford.emu.id.au
[groeck: Clarified subject]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/it87.c

@@ -87,6 +87,14 @@ static struct platform_device *it87_pdev[2];
 #define	DEVID	0x20	/* Register: Device ID */
 #define	DEVREV	0x22	/* Register: Device Revision */
 
+static inline void __superio_enter(int ioreg)
+{
+	outb(0x87, ioreg);
+	outb(0x01, ioreg);
+	outb(0x55, ioreg);
+	outb(ioreg == REG_4E ? 0xaa : 0x55, ioreg);
+}
+
 static inline int superio_inb(int ioreg, int reg)
 {
 	outb(reg, ioreg);
@@ -124,10 +132,7 @@ static inline int superio_enter(int ioreg)
 	if (!request_muxed_region(ioreg, 2, DRVNAME))
 		return -EBUSY;
 
-	outb(0x87, ioreg);
-	outb(0x01, ioreg);
-	outb(0x55, ioreg);
-	outb(ioreg == REG_4E ? 0xaa : 0x55, ioreg);
+	__superio_enter(ioreg);
 	return 0;
 }