core: fix flag formatting

checkpatch suggests using the BIT macro instead of a left shift.

Signed-off-by: Hernan Gatta <hegatta@microsoft.com>
Reviewed-by: Jerome Forissier <jerome@forissier.org>
[etienne: picked from OP-TEE#3673 series]
Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
Change-Id: I4806c99bede5a31bf19b18eb77e86284767fd3fc
Reviewed-on: https://gerrit.st.com/c/mpu/oe/optee/optee_os/+/202482
Tested-by: Etienne CARRIERE <etienne.carriere@foss.st.com>
Tested-by: Lionel DEBIEVE <lionel.debieve@foss.st.com>
Reviewed-by: Etienne CARRIERE <etienne.carriere@foss.st.com>
Reviewed-by: Lionel DEBIEVE <lionel.debieve@foss.st.com>

core/arch/arm/include/sm/optee_smc.h

@@ -6,6 +6,7 @@
 #define OPTEE_SMC_H
 
 #include <stdint.h>
+#include <util.h>
 
 /*
  * This file is exported by OP-TEE and is in kept in sync between secure