cmd: bcb: Fix duplicated handling in two case-branches

Fix warning V1037 reported by PVS-Studio Static Analyzer:
Two or more case-branches perform the same actions. Check lines: 49, 53

Fixes: db7b7a05b2 ("cmd: Add 'bcb' command to read/modify/write BCB fields")
Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Reviewed-by: Igor Opaniuk <igor.opaniuk@gmail.com>
Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>

cmd/bcb.c

@@ -46,9 +46,6 @@ static int bcb_is_misused(int argc, char *const argv[])
 
 	switch (cmd) {
 	case BCB_CMD_LOAD:
-		if (argc != 3)
-			goto err;
-		break;
 	case BCB_CMD_FIELD_SET:
 		if (argc != 3)
 			goto err;