usbdebug: Move ehci_debug_info allocation

Move ehci_debug_info allocation from console to lib, as console code
was only built for ramstage.

Implement dbgp_ehci_info() to return the EHCI context. Alread alias this
as dbgp_console_input() and _output() to return the console stream context
later on.

Change-Id: Id6cc07d62953f0466df61eeb159e22b0e3287d4e
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/3625
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@google.com>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/northbridge/intel/sandybridge/raminit.c

@@ -278,7 +278,7 @@ void sdram_initialize(struct pei_data *pei_data)
 
 #if CONFIG_USBDEBUG
 	/* mrc.bin reconfigures USB, so reinit it to have debug */
-	early_usbdebug_init();
+	usbdebug_init();
 #endif
 
 	/* For reference print the System Agent version