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/omap_hwmod_2420_data.c b/arch/arm/mach-omap2/omap_hwmod_2420_data.c
index 3efed3d..a8b3368 100644
--- a/arch/arm/mach-omap2/omap_hwmod_2420_data.c
+++ b/arch/arm/mach-omap2/omap_hwmod_2420_data.c
@@ -29,6 +29,7 @@
 #include "prm-regbits-24xx.h"
 #include "i2c.h"
 #include "mmc.h"
+#include "serial.h"
 #include "wd_timer.h"
 
 /*