x86: Conditionally build the pinctrl_ich6 driver

The pinctrl_ich6 driver is currently unconditionally built for all
x86 boards. Let's use a Kconfig option to control the build.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

arch/x86/Kconfig

@@ -735,6 +735,12 @@ config I8259_PIC
 	  slave) interrupt controllers. Include this to have U-Boot set up
 	  the interrupt correctly.
 
+config PINCTRL_ICH6
+	bool
+	help
+	  Intel ICH6 compatible chipset pinctrl driver. It needs to work
+	  together with the ICH6 compatible gpio driver.
+
 config I8254_TIMER
 	bool
 	default y

arch/x86/cpu/baytrail/Kconfig

@@ -12,6 +12,7 @@ config INTEL_BAYTRAIL
 	imply AHCI_PCI
 	imply ICH_SPI
 	imply INTEL_ICH6_GPIO
+	imply PINCTRL_ICH6
 	imply MMC
 	imply MMC_PCI
 	imply MMC_SDHCI

arch/x86/cpu/ivybridge/Kconfig

@@ -13,6 +13,7 @@ config NORTHBRIDGE_INTEL_IVYBRIDGE
 	imply AHCI_PCI
 	imply ICH_SPI
 	imply INTEL_ICH6_GPIO
+	imply PINCTRL_ICH6
 	imply SCSI
 	imply SCSI_AHCI
 	imply SPI_FLASH

arch/x86/lib/Makefile

@@ -24,7 +24,7 @@ obj-$(CONFIG_ENABLE_MRC_CACHE) += mrccache.o
 obj-y	+= northbridge-uclass.o
 obj-$(CONFIG_I8259_PIC) += i8259.o
 obj-$(CONFIG_I8254_TIMER) += i8254.o
-obj-y	+= pinctrl_ich6.o
+obj-$(CONFIG_PINCTRL_ICH6) += pinctrl_ich6.o
 obj-y	+= pirq_routing.o
 obj-y	+= relocate.o
 obj-y += physmem.o