scsi: esas2r: Add braces around the one-line if()

In certain configurations esas2r_bugon() is sometimes NULLed by the compiler.

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

 In file included from drivers/scsi/esas2r/esas2r_log.c:44:
 drivers/scsi/esas2r/esas2r.h: In function ‘esas2r_rq_init_request’:
 drivers/scsi/esas2r/esas2r.h:1229:17: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
 1229 | esas2r_bugon();
 | ^
 NB: Lots of these - snipped for brevity

Link: https://lore.kernel.org/r/20200723122446.1329773-33-lee.jones@linaro.org
Cc: Bradley Grove <linuxdrivers@attotech.com>
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/esas2r/esas2r.h

@@ -1225,8 +1225,9 @@ static inline void esas2r_rq_init_request(struct esas2r_request *rq,
 
 	/* req_table entry should be NULL at this point - if not, halt */
 
-	if (a->req_table[LOWORD(vrq->scsi.handle)])
+	if (a->req_table[LOWORD(vrq->scsi.handle)]) {
 		esas2r_bugon();
+	}
 
 	/* fill in the table for this handle so we can get back to the
 	 * request.