infiniband/qib: Fix typo in comment

Fix typo 'faspath' -> 'pastpath'.
Signed-off-by: NChengguang Xu <cgxu519@gmx.com>
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/qib/qib_common.h

@@ -57,7 +57,7 @@
  * QIB_VERBOSE_TRACING define as 1 if you want additional tracing in
  * fastpath code
  * QIB_TRACE_REGWRITES define as 1 if you want register writes to be
- * traced in faspath code
+ * traced in fastpath code
  * _QIB_TRACING define as 0 if you want to remove all tracing in a
  * compilation unit
  */