bus/fslmc: use DMB OSHST for synchronization before I/O
bus/fslmc: use DMB OSHST for synchronization before I/O

Outer Shareable Store (oshst) is sufficient for Data Memory
Barrier (dmb) when doing IO on the interface via QBMAN.

This will sync L3/DDR with the L1/L2 cached data.

Signed-off-by: Nipun Gupta <4871fd67344c57328097f2fd932ad9a0f1f1fe74@nxp.com>
Acked-by: Hemant Agrawal <90d96ef1ecd8ed49b97c7897be950e80824a9c5c@nxp.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk