ARM: OMAP2+: Remove legacy serial.c

We can now initialize the UARTs using device tree.

Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/Makefile

@@ -6,7 +6,7 @@ ccflags-y := -I$(srctree)/$(src)/include \
 	-I$(srctree)/arch/arm/plat-omap/include
 
 # Common support
-obj-y := id.o io.o control.o mux.o devices.o fb.o serial.o timer.o pm.o \
+obj-y := id.o io.o control.o mux.o devices.o fb.o timer.o pm.o \
 	 common.o gpio.o dma.o wd_timer.o display.o i2c.o hdq1w.o omap_hwmod.o \
 	 omap_device.o omap-headsmp.o sram.o drm.o