goldfish: refactor goldfish platform configs

On new virtual devices, the goldfish virtual bus can be replaced with
autoprobing infrastructure like Device Tree. Refactor the goldfish
kernel configs to better accommodate this.

Move the goldfish platform into a menuconfig in the style of the chrome
platform, and separate the goldfish bus into its own config option.

Signed-off-by: Greg Hackmann <[e-mail]>
Signed-off-by: Jin Qian <[e-mail]>
[Corrected a tristate to bool]
Signed-off-by: Alan Cox <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/platform/Kconfig

···
 if MIPS
 source "drivers/platform/mips/Kconfig"
 endif
-if GOLDFISH
+
 source "drivers/platform/goldfish/Kconfig"
-endif
 
 source "drivers/platform/chrome/Kconfig"

drivers/platform/goldfish/Kconfig

···
+menuconfig GOLDFISH
+	bool "Platform support for Goldfish virtual devices"
+	depends on X86_32 || X86_64 || ARM || ARM64
+	---help---
+	  Say Y here to get to see options for the Goldfish virtual platform.
+	  This option alone does not add any kernel code.
+
+	  Unless you are building for the Android Goldfish emulator say N here.
+
+if GOLDFISH
+
+config GOLDFISH_BUS
+	bool "Goldfish platform bus"
+	---help---
+	  This is a virtual bus to host Goldfish Android Virtual Devices.
+
 config GOLDFISH_PIPE
 	tristate "Goldfish virtual device for QEMU pipes"
 	---help---
 	  This is a virtual device to drive the QEMU pipe interface used by
 	  the Goldfish Android Virtual Device.
+
+endif # GOLDFISH

drivers/platform/goldfish/Makefile

···
 #
 # Makefile for Goldfish platform specific drivers
 #
-obj-$(CONFIG_GOLDFISH)	+=	pdev_bus.o
+obj-$(CONFIG_GOLDFISH_BUS)	+= pdev_bus.o
 obj-$(CONFIG_GOLDFISH_PIPE)	+= goldfish_pipe.o