fpga: region: fix kernel-doc

Fix function name in of-fpga-region.c kernel-doc comment
to remove a warning found by running scripts/kernel-doc,
which is caused by using 'make W=1'.

drivers/fpga/of-fpga-region.c:451: warning: expecting prototype for
fpga_region_init(). Prototype was for of_fpga_region_init() instead.

Reported-by: Abaci Robot <[e-mail]>
Signed-off-by: Yang Li <[e-mail]>
Acked-by: Randy Dunlap <[e-mail]>
Signed-off-by: Moritz Fischer <[e-mail]>

drivers/fpga/of-fpga-region.c

···
 };
 
 /**
- * fpga_region_init - init function for fpga_region class
+ * of_fpga_region_init - init function for fpga_region class
  * Creates the fpga_region class and registers a reconfig notifier.
  */
 static int __init of_fpga_region_init(void)