This patch fixes several issues with the SP804 delay timer on FVP:

* By default, the SP804 dual timer on FVP runs at 32 KHz. In order
  to run the timer at 35 MHz (as specified in the FVP user manual)
  the Overwrite bit in the SP810 control register must be set.

* The CLKMULT and CLKDIV definitions are mixed up:

      delta(us) = delta(ticks) * T(us) = delta(ticks) / f(MHz)

  From the delay function:

      delta_us = (delta * ops->clk_mult) / ops->clk_div;

  Matching both expressions:

      1 / f(MHz) = ops->clk_mult / ops->clk_div

  And consequently:

      f(MHz) = ops->clk_div / ops->clk_mult

  Which, for a 35 MHz timer, translates to:

      ops->clk_div = 35
      ops->clk_mult = 1

* The comment in the delay timer header file has been corrected:
  The ratio of the multiplier and the divider is the clock period
  in microseconds, not the frequency.

Change-Id: Iffd5ce0a5a28fa47c0720c0336d81b678ff8fdf1

Add SP804 delay timer support to the FVP BSP.

This commit simply provides the 3 constants needed by the SP804
delay timer driver and calls sp804_timer_init() in
bl2_platform_setup(). The BSP does not currently use the delay
timer functions.

Note that the FVP SP804 is a normal world accessible peripheral
and should not be used by the secure world after transition
to the normal world.

Change-Id: I5f91d2ac9eb336fd81943b3bb388860dfb5f2b39
Co-authored-by: Dan Handley <dan.handley@arm.com>

Move the FVP port from plat/fvp to plat/arm/board/fvp. Also rename
some of the files so they are consistently prefixed with fvp_.
Update the platform makefiles accordingly.

Change-Id: I7569affc3127d66405f1548fc81b878a858e61b7