netarm: move serial driver to drivers/serial

add CONFIG_NETARM_SERIAL to activate the driver

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index 8cac794..e76a2ad 100644
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -35,6 +35,7 @@
 COBJS-$(CONFIG_SYS_NS16550_SERIAL) += serial.o
 COBJS-$(CONFIG_IXP_SERIAL) += serial_ixp.o
 COBJS-$(CONFIG_MAX3100_SERIAL) += serial_max3100.o
+COBJS-$(CONFIG_NETARM_SERIAL) += serial_netarm.o
 COBJS-$(CONFIG_PL010_SERIAL) += serial_pl01x.o
 COBJS-$(CONFIG_PL011_SERIAL) += serial_pl01x.o
 COBJS-$(CONFIG_SA1100_SERIAL) += serial_sa1100.o