ARM: Add workaround for Cortex-A9 errata 761320

Full cache line writes to the same memory region from at least two
processors might deadlock the processor. Exists on r1, r2, r3
revisions.

Signed-off-by: Nitin Garg <nitin.garg@freescale.com>
Acked-by: Fabio Estevam <fabio.estevam@freescale.com>