arm: zynq: U-Boot udelay < 1000 FIX

Rework the __udelay function of U-Boot Zynq Arch to handle
delay < 1000 usec

Signed-off-by: David Andrey <david.andrey@netmodule.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Tom Rini <trini@ti.com>
1 file changed