doc: Update the zynq u-boot status

NAND and QSPI devices are now supported, so mark
them as such.

Cc: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
1 file changed