i2c: mux: pinctrl: mention correct module name in Kconfig help text

Kconfig says the resulting module is pinctrl-i2cmux, but the module when
built is i2c-mux-pinctrl.

Fixes: ae58d1e40698 ("i2c: Add generic I2C multiplexer using pinctrl API")
Signed-off-by: Chris Gorman <chrisjohgorman@gmail.com>
Signed-off-by: Peter Rosin <peda@axentia.se>

drivers/i2c/muxes/Kconfig

@@ -83,7 +83,7 @@ config I2C_MUX_PINCTRL
 	  different sets of pins at run-time.
 
 	  This driver can also be built as a module. If so, the module will be
-	  called pinctrl-i2cmux.
+	  called i2c-mux-pinctrl.
 
 config I2C_MUX_REG
 	tristate "Register-based I2C multiplexer"