libpayload: Add support for the CBMEM in memory console.

Change-Id: I1489b5306ef1ca078686fed4dba2d242f70ad941
Signed-off-by: Gabe Black <gabeblack@google.com>
Reviewed-on: http://review.coreboot.org/1727
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

payloads/libpayload/drivers/Makefile.inc

@@ -37,6 +37,8 @@ libc-$(CONFIG_SERIAL_CONSOLE) += serial.c
 
 libc-$(CONFIG_PC_KEYBOARD) += keyboard.c
 
+libc-$(CONFIG_CBMEM_CONSOLE) += cbmem_console.c
+
 libc-$(CONFIG_NVRAM) += nvram.c
 libc-$(CONFIG_NVRAM) += options.c