zynq: Remove USB PHY out of reset in board_init

The USB PHY out of reset is validated in fsbl, hence removed
this hack from board_init.

Signed-off-by: Siva Durga Prasad Paladugu <sivadur@xilinx.com>
Signed-off-by: Jagannadha Sutradharudu Teki <jaganna@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>