[XTENSA] Add typecast macro for constants

Add macros (__XTENSA_UL and __XTENSA_UL_CONST) for typecasting
constants.

Signed-off-by: Chris Zankel <chris@zankel.net>
diff --git a/include/asm-xtensa/processor.h b/include/asm-xtensa/processor.h
index 4feb9f7..35145bc 100644
--- a/include/asm-xtensa/processor.h
+++ b/include/asm-xtensa/processor.h
@@ -33,7 +33,7 @@
  * the 1 GB requirement applies to the stack as well.
  */
 
-#define TASK_SIZE	0x40000000
+#define TASK_SIZE	__XTENSA_UL_CONST(0x40000000)
 
 /*
  * General exception cause assigned to debug exceptions. Debug exceptions go