gpio: aspeed-sgpio: Rename and add Kconfig/Makefile

This renames the "gpio-aspeed" driver to conform with other
GPIO drivers as "gpio-aspeed-sgpio.c". All GPIO drivers
should start with the string "gpio-" no special exceptions.

Also the Kconfig and Makefile entries should normally
go with the driver but I missed this in my review, sorry
for mistake. "CONFIG_GPIO_ASPEED_SGPIO" is used to
activate this driver.

Cc: Hongwei Zhang <hongweiz@ami.com>
Fixes: 7db47faa ("gpio: aspeed: Add SGPIO driver")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Andrew Jeffery <andrew@aj.id.au>
Link: https://lore.kernel.org/r/20190927114833.12551-1-linus.walleij@linaro.org

drivers/gpio/Kconfig

@@ -120,6 +120,14 @@ config GPIO_ASPEED
 	help
 	  Say Y here to support Aspeed AST2400 and AST2500 GPIO controllers.
 
+config GPIO_ASPEED_SGPIO
+	bool "Aspeed SGPIO support"
+	depends on (ARCH_ASPEED || COMPILE_TEST) && OF_GPIO
+	select GPIO_GENERIC
+	select GPIOLIB_IRQCHIP
+	help
+	  Say Y here to support Aspeed AST2500 SGPIO functionality.
+
 config GPIO_ATH79
 	tristate "Atheros AR71XX/AR724X/AR913X GPIO support"
 	default y if ATH79

drivers/gpio/Makefile

@@ -32,6 +32,7 @@ obj-$(CONFIG_GPIO_AMD_FCH)		+= gpio-amd-fch.o
 obj-$(CONFIG_GPIO_AMDPT)		+= gpio-amdpt.o
 obj-$(CONFIG_GPIO_ARIZONA)		+= gpio-arizona.o
 obj-$(CONFIG_GPIO_ASPEED)		+= gpio-aspeed.o
+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_BD70528)		+= gpio-bd70528.o