scsi: lpfc: Use __printf() format notation

Fixes the following W=1 kernel build warning(s):

 drivers/scsi/lpfc/lpfc_init.c: In function ‘lpfc_dbg_print’:
 drivers/scsi/lpfc/lpfc_init.c:14212:6: warning: function ‘lpfc_dbg_print’ might be a candidate for ‘gnu_printf’ format attribute [-Wsuggest-attribute=format]
 14212 | sizeof(phba->dbg_log[idx].log), fmt, args);
 | ^~~~~~

Link: https://lore.kernel.org/r/20200723122446.1329773-16-lee.jones@linaro.org
Cc: James Smart <james.smart@broadcom.com>
Cc: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/lpfc/lpfc_init.c

@@ -14186,6 +14186,7 @@ void lpfc_dmp_dbg(struct lpfc_hba *phba)
 	atomic_set(&phba->dbg_log_dmping, 0);
 }
 
+__printf(2, 3)
 void lpfc_dbg_print(struct lpfc_hba *phba, const char *fmt, ...)
 {
 	unsigned int idx;