arm: socfpga: Drop space after 'loadaddr=' in extra env

There is an incorrect space after loadaddr= in the extra environment,
so drop it.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Dinh Nguyen <dinguyen@opensource.altera.com>
Cc: Chin Liang See <clsee@altera.com>