scsi: mpi3mr: Remove unnecessary cast

coccinelle reports a warning:

  WARNING: casting value returned by memory allocation function to (struct
  mpi3mr_throttle_group_info *) is useless

To fix this, the unnecessary cast is removed.

Link: https://lore.kernel.org/r/Yx+kp8NxHvDHs7dv@playgroundSigned-off-by: Jules Irenge <jbi.octave@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/mpi3mr/mpi3mr_fw.c

@@ -3894,8 +3894,7 @@ int mpi3mr_init_ioc(struct mpi3mr_ioc *mrioc)
 	if (!mrioc->throttle_groups && mrioc->num_io_throttle_group) {
 		dprint_init(mrioc, "allocating memory for throttle groups\n");
 		sz = sizeof(struct mpi3mr_throttle_group_info);
-		mrioc->throttle_groups = (struct mpi3mr_throttle_group_info *)
-		    kcalloc(mrioc->num_io_throttle_group, sz, GFP_KERNEL);
+		mrioc->throttle_groups = kcalloc(mrioc->num_io_throttle_group, sz, GFP_KERNEL);
 		if (!mrioc->throttle_groups)
 			goto out_failed_noretry;
 	}