x86: usb debug port early console, fix

fix:

 arch/x86/kernel/built-in.o: In function `nvidia_set_debug_port':
 early_printk.c:(.text+0xf8b1): undefined reference to `read_pci_config'
 early_printk.c:(.text+0xf8dc): undefined reference to `write_pci_config'
 arch/x86/kernel/built-in.o: In function `setup_early_printk':
 early_printk.c:(.init.text+0x5487): undefined reference to `early_pci_allowed'
 early_printk.c:(.init.text+0x54cb): undefined reference to `read_pci_config'
 early_printk.c:(.init.text+0x54ec): undefined reference to `read_pci_config_16'
 [...]

Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/Kconfig.debug

@@ -46,7 +46,7 @@ config EARLY_PRINTK
 config EARLY_PRINTK_DBGP
 	bool "Early printk via EHCI debug port"
 	default n
-	depends on EARLY_PRINTK
+	depends on EARLY_PRINTK && PCI
 	help
 	  Write kernel log output directly into the EHCI debug port.