CXGBE: fix big-endian behaviour

The setbit/clearbit pair casts the bitfield pointer
to uint8_t* which effectively treats its contents as
little-endian variable. The ffs() function accepts int as
the parameter, which is big-endian. Use uint8_t here to
avoid mismatch, as we have only 4 doorbells.

Submitted by:          Wojciech Macek <[email protected]>
Reviewed by:           np
Obtained from:         Semihalf
Sponsored by:          QCM Technologies
Differential revision: https://reviews.freebsd.org/D13084

sys/dev/cxgbe/adapter.h

@@ -424,7 +424,7 @@ struct sge_eq {
 	struct mtx eq_lock;
 
 	struct tx_desc *desc;	/* KVA of descriptor ring */
-	uint16_t doorbells;
+	uint8_t doorbells;
 	volatile uint32_t *udb;	/* KVA of doorbell (lies within BAR2) */
 	u_int udb_qid;		/* relative qid within the doorbell page */
 	uint16_t sidx;		/* index of the entry with the status page */
@@ -695,7 +695,7 @@ struct sge_nm_txq {
 	uint16_t equiqidx;	/* EQUIQ last requested at this pidx */
 	uint16_t equeqidx;	/* EQUEQ last requested at this pidx */
 	uint16_t dbidx;		/* pidx of the most recent doorbell */
-	uint16_t doorbells;
+	uint8_t doorbells;
 	volatile uint32_t *udb;
 	u_int udb_qid;
 	u_int cntxt_id;
@@ -807,7 +807,7 @@ struct adapter {
 	struct l2t_data *l2t;	/* L2 table */
 	struct tid_info tids;
 
-	uint16_t doorbells;
+	uint8_t doorbells;
 	int offload_map;	/* ports with IFCAP_TOE enabled */
 	int active_ulds;	/* ULDs activated on this adapter */
 	int flags;