x86: sandbox: pch: Add a CONFIG option for PCH

At present this uclass is selected only on x86. In order to add a test for
it, it must also support sandbox. Create a new CONFIG_PCH option and
enable it on x86 and sandbox.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/Kconfig b/arch/Kconfig
index 35e2712..d9afe26 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -117,6 +117,7 @@
 	imply VIRTIO_BLK
 	imply VIRTIO_NET
 	imply DM_SOUND
+	imply PCH
 
 config SH
 	bool "SuperH architecture"
@@ -160,6 +161,7 @@
 	imply USB_ETHER_ASIX
 	imply USB_ETHER_SMSC95XX
 	imply USB_HOST_ETHER
+	imply PCH
 
 config XTENSA
 	bool "Xtensa architecture"