The generic delay timer driver expects a pointer to a timer_ops_t
structure containing the specific timer driver information. It
doesn't make a copy of the structure, instead it just keeps the
pointer. Therefore, this pointer must remain valid over time.

The SP804 driver doesn't satisfy this requirement. The
sp804_timer_init() macro creates a temporary instanciation of the
timer_ops_t structure on the fly and passes it to the generic
delay timer. When this temporary instanciation gets deallocated,
the generic delay timer is left with a pointer to invalid data.

This patch fixes this bug by statically allocating the SP804
timer_ops_t structure.

Change-Id: I8fbf75907583aef06701e3fd9fabe0b2c9bc95bf

Add a delay timer driver for the ARM SP804 dual timer.

This driver only uses the first timer, called timer 1 in the
SP804 Technical Reference Manual (ARM DDI 0271D).

To use this driver, the BSP must provide three constants:

*   The base address of the SP804 dual timer
*   The clock multiplier
*   The clock divider

The BSP is responsible for calling sp804_timer_init(). The SP804
driver instantiates a constant timer_ops_t and calls the generic
timer_init().

Change-Id: I49ba0a52bdf6072f403d1d0a20e305151d4bc086
Co-authored-by: Dan Handley <dan.handley@arm.com>