x86: Allow removal of standard PCH drivers

These drivers are not needed on all platforms. While they are small, it
is useful in TPL to drop then. Add Kconfig control to allow this.

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

drivers/pch/Kconfig

@@ -7,3 +7,21 @@ config PCH
 	  northbridge / southbridge architecture that was previously used. The
 	  PCH allows for higher performance since the memory functions are
 	  handled in the CPU.
+
+config X86_PCH7
+	bool "Add support for Intel PCH7"
+	default y if X86
+	help
+	  Enable this if your SoC uses Platform Controller Hub 7 (PCH7). This
+	  dates from about 2011 and is used on baytrail, for example. The
+	  PCH provides access to the GPIO and SPI base addresses, among other
+	  functions.
+
+config X86_PCH9
+	bool "Add support for Intel PCH9"
+	default y if X86
+	help
+	  Enable this if your SoC uses Platform Controller Hub 9 (PCH9). This
+	  dates from about 2015 and is used on baytrail, for example. The
+	  PCH provides access to the GPIO and SPI base addresses, among other
+	  functions.

drivers/pch/Makefile

@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0+
 
 obj-y += pch-uclass.o
-obj-y += pch7.o
-obj-y += pch9.o
+obj-$(CONFIG_X86_PCH7) += pch7.o
+obj-$(CONFIG_X86_PCH9) += pch9.o
 obj-$(CONFIG_SANDBOX) += sandbox_pch.o