ARM: mvebu: add workaround for data abort issue on Armada 375

Early versions of Armada 375 SoC have a bug where the BootROM leaves
an external data abort pending. The kernel is hit by this data abort
as soon as it enters userspace, because it unmasks the data aborts at
this moment. We register a custom abort handler below to ignore the
first data abort to work around this problem.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>