core: arm64: add dsb_osh()

Implement the use of osh data barrier to ensure that all data
access and modifications have been completed before executing
subsequent instructions.

Signed-off-by: Xiaoxu Zeng <zengxiaoxu@huawei.com>
Reviewed-by: Jerome Forissier <jerome.forissier@linaro.org>
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>

core/arch/arm/include/arm64.h

@@ -296,6 +296,11 @@ static inline __noprof void dsb_ishst(void)
 	asm volatile ("dsb ishst" : : : "memory");
 }
 
+static inline __noprof void dsb_osh(void)
+{
+	asm volatile ("dsb osh" : : : "memory");
+}
+
 static inline __noprof void sev(void)
 {
 	asm volatile ("sev" : : : "memory");