Documentation: ACPI: i2c-muxes: fix I2C device references

When the device references were changed from relative to absolute in
commit e65cb011349e ("Documentation: ACPI: Fix parent device
references"), the MUX0 device was omitted from the paths.

So add it to fix the references.

Fixes: e65cb011349e ("Documentation: ACPI: Fix parent device references")
Closes: https://lore.kernel.org/all/[e-mail]/
Signed-off-by: Jonas Gorski <[e-mail]>
Reviewed-by: Andy Shevchenko <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Rafael J. Wysocki <[e-mail]>

Documentation/firmware-guide/acpi/i2c-muxes.rst

···
                     Name (_HID, ...)
                     Name (_CRS, ResourceTemplate () {
                         I2cSerialBus (0x50, ControllerInitiated, I2C_SPEED,
-                                    AddressingMode7Bit, "\\_SB.SMB1.CH00", 0x00,
-                                    ResourceConsumer,,)
+                                    AddressingMode7Bit, "\\_SB.SMB1.MUX0.CH00",
+                                    0x00, ResourceConsumer,,)
                     }
                 }
             }
···
                     Name (_HID, ...)
                     Name (_CRS, ResourceTemplate () {
                         I2cSerialBus (0x50, ControllerInitiated, I2C_SPEED,
-                                    AddressingMode7Bit, "\\_SB.SMB1.CH01", 0x00,
-                                    ResourceConsumer,,)
+                                    AddressingMode7Bit, "\\_SB.SMB1.MUX0.CH01",
+                                    0x00, ResourceConsumer,,)
                     }
                 }
             }