IB/hfi1: Move a function from a header file into a .c file

Since ib_get_len() only has one caller, move it from a header file into a
.c file. Additionally, remove the superfluous u16 cast. That cast was
introduced by commit 7dafbab3 ("IB/hfi1: Add functions to parse BTH/IB
headers").

Link: https://lore.kernel.org/r/20210524041211.9480-2-bvanassche@acm.org
Cc: Don Hiatt <don.hiatt@intel.com>
Cc: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/hfi1/trace.c

@@ -189,6 +189,11 @@ void hfi1_trace_parse_16b_bth(struct ib_other_headers *ohdr,
 	*qpn = ib_bth_get_qpn(ohdr);
 }
 
+static u16 ib_get_len(const struct ib_header *hdr)
+{
+	return be16_to_cpu(hdr->lrh[2]);
+}
+
 void hfi1_trace_parse_9b_hdr(struct ib_header *hdr, bool sc5,
 			     u8 *lnh, u8 *lver, u8 *sl, u8 *sc,
 			     u16 *len, u32 *dlid, u32 *slid)

include/rdma/ib_hdrs.h

@@ -206,11 +206,6 @@ static inline u8 ib_get_lver(struct ib_header *hdr)
 		   IB_LVER_MASK);
 }
 
-static inline u16 ib_get_len(struct ib_header *hdr)
-{
-	return (u16)(be16_to_cpu(hdr->lrh[2]));
-}
-
 static inline u32 ib_get_qkey(struct ib_other_headers *ohdr)
 {
 	return be32_to_cpu(ohdr->u.ud.deth[0]);