mfd: Kconfig: Fix typo in PMIC_ADP5520 from AD5520 to ADP5520

The description mentioned AD5520, which is a different device.
Fixed the typo.
Signed-off-by: Ramona Alexandra Nechita <ramona.nechita@analog.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/Kconfig

@@ -93,7 +93,7 @@ config PMIC_ADP5520
 	bool "Analog Devices ADP5520/01 MFD PMIC Core Support"
 	depends on I2C=y
 	help
-	  Say yes here to add support for Analog Devices AD5520 and ADP5501,
+	  Say yes here to add support for Analog Devices ADP5520 and ADP5501,
 	  Multifunction Power Management IC. This includes
 	  the I2C driver and the core APIs _only_, you have to select
 	  individual components like LCD backlight, LEDs, GPIOs and Kepad