IB/core, cma: Make __attribute_const__ declarations sparse-friendly

Move the __attribute_const__ declarations such that sparse understands
that these apply to the function itself and not to the return type.
This avoids that sparse reports error messages like the following:

drivers/infiniband/core/verbs.c:73:12: error: symbol 'ib_event_msg' redeclared with different type (originally declared at include/rdma/ib_verbs.h:470) - different modifiers

Fixes: 2b1b5b601230 ("IB/core, cma: Nice log-friendly string helpers")
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
diff --git a/include/rdma/rdma_cm.h b/include/rdma/rdma_cm.h
index 463ec0c..afe44fd 100644
--- a/include/rdma/rdma_cm.h
+++ b/include/rdma/rdma_cm.h
@@ -62,7 +62,7 @@
 	RDMA_CM_EVENT_TIMEWAIT_EXIT
 };
 
-__attribute_const__ const char *rdma_event_msg(enum rdma_cm_event_type event);
+const char *__attribute_const__ rdma_event_msg(enum rdma_cm_event_type event);
 
 enum rdma_port_space {
 	RDMA_PS_SDP   = 0x0001,