gpio: bd70528 Drop BD70528 support

The only known BD70528 use-cases are such that the PMIC is controlled
from separate MCU which is not running Linux. I am not aware of
any Linux driver users. Furthermore, it seems there is no demand for
this IC. Let's ease the maintenance burden and drop the driver. We can
always add it back if there is sudden need for it.

Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Acked-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/4eff6bd5eff8afc137dd8c1697cb5c6b2e3aacd2.1637066805.git.matti.vaittinen@fi.rohmeurope.com

drivers/gpio/Kconfig

@@ -1132,17 +1132,6 @@ config GPIO_ARIZONA
 	help
 	  Support for GPIOs on Wolfson Arizona class devices.
 
-config GPIO_BD70528
-	tristate "ROHM BD70528 GPIO support"
-	depends on MFD_ROHM_BD70528
-	help
-	  Support for GPIOs on ROHM BD70528 PMIC. There are four GPIOs
-	  available on the ROHM PMIC in total. The GPIOs can also
-	  generate interrupts.
-
-	  This driver can also be built as a module. If so, the module
-	  will be called gpio-bd70528.
-
 config GPIO_BD71815
 	tristate "ROHM BD71815 PMIC GPIO support"
 	depends on MFD_ROHM_BD71828

drivers/gpio/Makefile

@@ -38,7 +38,6 @@ obj-$(CONFIG_GPIO_ASPEED_SGPIO)		+= gpio-aspeed-sgpio.o
 obj-$(CONFIG_GPIO_ATH79)		+= gpio-ath79.o
 obj-$(CONFIG_GPIO_BCM_KONA)		+= gpio-bcm-kona.o
 obj-$(CONFIG_GPIO_BCM_XGS_IPROC)	+= gpio-xgs-iproc.o
-obj-$(CONFIG_GPIO_BD70528)		+= gpio-bd70528.o
 obj-$(CONFIG_GPIO_BD71815)		+= gpio-bd71815.o
 obj-$(CONFIG_GPIO_BD71828)		+= gpio-bd71828.o
 obj-$(CONFIG_GPIO_BD9571MWV)		+= gpio-bd9571mwv.o