Update base code to not rely on undefined overflow behaviour

This consists of ensuring that the left operand of each shift is
unsigned when the operation might overflow into the sign bit.

Change-Id: Iddd6f38139a4c6e500468b4fc48d04e0939f574e
Signed-off-by: Justin Chadwell <justin.chadwell@arm.com>
diff --git a/include/drivers/ufs.h b/include/drivers/ufs.h
index a10cd80..574c4ea 100644
--- a/include/drivers/ufs.h
+++ b/include/drivers/ufs.h
@@ -82,7 +82,7 @@
 #define UECDME				0x48
 /* UTP Transfer Request Interrupt Aggregation Control Register */
 #define UTRIACR				0x4C
-#define UTRIACR_IAEN			(1 << 31)
+#define UTRIACR_IAEN			(1U << 31)
 #define UTRIACR_IAPWEN			(1 << 24)
 #define UTRIACR_IASB			(1 << 20)
 #define UTRIACR_CTR			(1 << 16)