lib: utils: Add simple FDT serial framework

We add simple serial framework which will select and use serial driver
based on details in FDT passed by previous booting stage.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

lib/utils/serial/objects.mk

@@ -7,5 +7,9 @@
 #   Anup Patel <anup.patel@wdc.com>
 #
 
+libsbiutils-objs-y += serial/fdt_serial.o
+libsbiutils-objs-y += serial/fdt_serial_htif.o
+libsbiutils-objs-y += serial/fdt_serial_sifive.o
+libsbiutils-objs-y += serial/fdt_serial_uart8250.o
 libsbiutils-objs-y += serial/sifive-uart.o
 libsbiutils-objs-y += serial/uart8250.o