docs/sp_SP: Add translation of process/adding-syscalls

Translate Documentation/process/adding-syscalls.rst into Spanish.

Co-developed-by: Mauricio Fuentes <mauriciofb@gmail.com>
Signed-off-by: Mauricio Fuentes <mauriciofb@gmail.com>
Signed-off-by: Carlos Bilbao <carlos.bilbao@amd.com>
Link: https://lore.kernel.org/r/20230315143526.1213813-1-carlos.bilbao@amd.com