Mark switch cases where we are expecting to fall through.

This patch fixes the following warnings:

drivers/scsi/cxlflash/main.c: In function 'send_afu_cmd':
drivers/scsi/cxlflash/main.c:2347:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if (rc) {
      ^
drivers/scsi/cxlflash/main.c:2357:2: note: here
  case -EAGAIN:
  ^~~~
drivers/scsi/cxlflash/main.c: In function 'term_intr':
drivers/scsi/cxlflash/main.c:754:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if (index == PRIMARY_HWQ)
      ^
drivers/scsi/cxlflash/main.c:756:2: note: here
  case UNMAP_TWO:
  ^~~~
drivers/scsi/cxlflash/main.c:757:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
   cfg->ops->unmap_afu_irq(hwq->ctx_cookie, 2, hwq);
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/scsi/cxlflash/main.c:758:2: note: here
  case UNMAP_ONE:
  ^~~~
drivers/scsi/cxlflash/main.c:759:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
   cfg->ops->unmap_afu_irq(hwq->ctx_cookie, 1, hwq);
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/scsi/cxlflash/main.c:760:2: note: here
  case FREE_IRQ:
  ^~~~
drivers/scsi/cxlflash/main.c: In function 'cxlflash_remove':
drivers/scsi/cxlflash/main.c:975:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
   cxlflash_release_chrdev(cfg);
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/scsi/cxlflash/main.c:976:2: note: here
  case INIT_STATE_SCSI:
  ^~~~
drivers/scsi/cxlflash/main.c:978:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
   scsi_remove_host(cfg->host);
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/scsi/cxlflash/main.c:979:2: note: here
  case INIT_STATE_AFU:
  ^~~~
drivers/scsi/cxlflash/main.c:980:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
   term_afu(cfg);
   ^~~~~~~~~~~~~
drivers/scsi/cxlflash/main.c:981:2: note: here
  case INIT_STATE_PCI:
  ^~~~
drivers/scsi/cxlflash/main.c:983:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
   pci_disable_device(pdev);
   ^~~~~~~~~~~~~~~~~~~~~~~~
drivers/scsi/cxlflash/main.c:984:2: note: here
  case INIT_STATE_NONE:
  ^~~~
drivers/scsi/cxlflash/main.c: In function 'num_hwqs_store':
drivers/scsi/cxlflash/main.c:3018:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if (cfg->state == STATE_NORMAL)
      ^
drivers/scsi/cxlflash/main.c:3020:2: note: here
  default:
  ^~~~~~~
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Matthew R. Ochs <mrochs@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>