serial: Move common/serial.c to drivers/serial/

Move the common/serial.c into driver/serial/, since this file
provides serial multiplexing functions and it is imperative to
be linked with libserial.o instead of libcommon.o.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Marek Vasut <marek.vasut@gmail.com>
Cc: Tom Rini <trini@ti.com>

common/Makefile

@@ -32,7 +32,6 @@ COBJS-y += command.o
 COBJS-y += exports.o
 COBJS-$(CONFIG_SYS_HUSH_PARSER) += hush.o
 COBJS-y += s_record.o
-COBJS-$(CONFIG_SERIAL_MULTI) += serial.o
 COBJS-y += xyzModem.o
 COBJS-y += cmd_disk.o
 

drivers/serial/Makefile

@@ -25,6 +25,10 @@ include $(TOPDIR)/config.mk
 
 LIB	:= $(obj)libserial.o
 
+ifndef CONFIG_SPL_BUILD
+COBJS-$(CONFIG_SERIAL_MULTI) += serial.o
+endif
+
 COBJS-$(CONFIG_ALTERA_UART) += altera_uart.o
 COBJS-$(CONFIG_ALTERA_JTAG_UART) += altera_jtag_uart.o
 COBJS-$(CONFIG_ARM_DCC) += arm_dcc.o