[ARM] S3C24XX: Move vmalloc.h to plat-s3c

vmalloc.h is common across all the current s3c platforms,
so move it to arch/arm/plat-s3c/include/mach to be used
for all the targets.
Signed-off-by: NBen Dooks <ben-linux@fluff.org>

arch/arm/mach-s3c2410/include/mach/vmalloc.h → arch/arm/plat-s3c/include/mach/vmalloc.h

-/* arch/arm/mach-s3c2410/include/mach/vmalloc.h
+/* arch/arm/plat-s3c/include/mach/vmalloc.h
  *
  * from arch/arm/mach-iop3xx/include/mach/vmalloc.h
  *