fpga: fix alignment on fpga cmd usage info

fpga: fix alignment on fpga cmd usage info

The current implementation generates some alignment issues as well as
some overlapping when all the fpga command options are enabled. The fix
is intended to improve readability of the usage info.

Signed-off-by: Ibai Erkiaga <ibai.erkiaga-elorza@amd.com>
Acked-by: Alexander Dahl <ada@thorsis.com>
Link: https://lore.kernel.org/r/20250121130138.1999916-2-ibai.erkiaga-elorza@amd.com
Signed-off-by: Michal Simek <michal.simek@amd.com>