cbtypes.h: Unify cbtypes.h used in AMD board's code

Remove all the repeated sections of code in cbtypes.h and place it
in a common location. Add include dir in vendor code's Makefile.

Change-Id: Ida92c2a7a88e9520b84b0dcbbf37cd5c9f63f798
Signed-off-by: Vikram Narayanan <vikram186@gmail.com>
Reviewed-on: http://review.coreboot.org/912
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marcj303@gmail.com>

src/mainboard/amd/torpedo/gpio.h

@@ -27,7 +27,7 @@
 #define _GPIO_H_
 
 #include <stdint.h>
-#include <cbtypes.h>
+#include <cpu/amd/common/cbtypes.h>
 
 /*----------------------------------------------------------------------------------------
  *                   D E F I N I T I O N S    A N D    M A C R O S