ppc4xx: Rework of 4xx serial driver (3)

Change all linker scripts to reference the changed driver name iop480_uart.o.

Signed-off-by: Stefan Roese <sr@denx.de>

board/esd/dasa_sim/u-boot.lds

@@ -64,7 +64,7 @@ SECTIONS
     cpu/ppc4xx/start.o		(.text)
     cpu/ppc4xx/traps.o		(.text)
     cpu/ppc4xx/interrupts.o	(.text)
-    cpu/ppc4xx/serial.o		(.text)
+    cpu/ppc4xx/iop480_uart.o	(.text)
     cpu/ppc4xx/cpu_init.o	(.text)
     cpu/ppc4xx/speed.o		(.text)
     common/dlmalloc.o		(.text)