ARM: OMAP: Split plat/serial.h for omap1 and omap2+

For omap1, we'll keep mach/serial.h around for 8250.c hardware
workarounds. For omap2+, we no longer need mach/serial.h and
can make it local to mach-omap2.

Signed-off-by: Tony Lindgren <tony@atomide.com>
diff --git a/arch/arm/mach-omap2/io.c b/arch/arm/mach-omap2/io.c
index 80d1cf1..4fadc78 100644
--- a/arch/arm/mach-omap2/io.c
+++ b/arch/arm/mach-omap2/io.c
@@ -25,7 +25,6 @@
 #include <asm/tlb.h>
 #include <asm/mach/map.h>
 
-#include <plat/serial.h>
 #include <plat-omap/dma-omap.h>
 
 #include "../plat-omap/sram.h"
@@ -43,6 +42,7 @@
 #include "clock44xx.h"
 #include "omap-pm.h"
 #include "sdrc.h"
+#include "serial.h"
 
 /*
  * The machine specific code may provide the extra mapping besides the