ARMV7: Versatile Express Coretile CortexA9x4 support

Adds support for the ARM quad-core Cortex-A9 processor

This system includes a motherboard(Versatile Express), daughterboard
(Coretile), and SOC(Cortex-A9 quad core).  The serial port, ethernet,
and flash systems work with these additions.  The naming convention
is:
   SOC -> CortexA9 quad core = ca9x4
   daughterboard -> Coretile = ct
   motherboard -> Versatile Express = vxp
This gives ca9x4_ct_vxp.c as the board support file.

Signed-off-by: Matt Waddel <matt.waddel@linaro.org>