serial: pch_uart: Fix Kconfig dependencies

The pch_uart driver is for a companion chip to the Intel Atom E600
series processors. These are 32-bit x86 processors so the driver is
only needed on X86_32. Add COMPILE_TEST as an alternative, so that the
driver can still be build-tested elsewhere.
Signed-off-by: NJean Delvare <jdelvare@suse.de>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/Kconfig

@@ -1351,7 +1351,7 @@ config SERIAL_IFX6X60
 
 config SERIAL_PCH_UART
 	tristate "Intel EG20T PCH/LAPIS Semicon IOH(ML7213/ML7223/ML7831) UART"
-	depends on PCI
+	depends on PCI && (X86_32 || COMPILE_TEST)
 	select SERIAL_CORE
 	help
 	  This driver is for PCH(Platform controller Hub) UART of Intel EG20T