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/drivers/Makefile b/drivers/Makefile
index eca023a..a7bba3e 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -86,7 +86,8 @@
 obj-$(CONFIG_MMC) += mmc/
 obj-$(CONFIG_NVME) += nvme/
 obj-y += pcmcia/
-obj-$(CONFIG_X86) += pch/
+obj-y += dfu/
+obj-$(CONFIG_PCH) += pch/
 obj-y += phy/allwinner/
 obj-y += phy/marvell/
 obj-y += rtc/