davinci: include correct header file for dm646x specific code

Make the dm646x.c specific code include the dm646x.h include file and
not dm644x.h.
Signed-off-by: Mark A. Greer <mgreer@mvista.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>

arch/arm/mach-davinci/dm646x.c

@@ -12,7 +12,7 @@
 #include <linux/init.h>
 #include <linux/clk.h>
 
-#include <mach/dm644x.h>
+#include <mach/dm646x.h>
 #include <mach/clock.h>
 #include <mach/psc.h>
 #include <mach/mux.h>