target: trace: drop useless typedef trace_status_t

No need to use a typedef for an enum.
Drop it.

Change-Id: I31e0e3869c7277bcb14e05cfcac82c9655963ae6
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/8704
Tested-by: jenkins
Reviewed-by: zapb <dev@zapb.de>

src/target/etm_dummy.c

@@ -65,7 +65,7 @@ static int etm_dummy_init(struct etm_context *etm_ctx)
 	return ERROR_OK;
 }
 
-static trace_status_t etm_dummy_status(struct etm_context *etm_ctx)
+static enum trace_status etm_dummy_status(struct etm_context *etm_ctx)
 {
 	return TRACE_IDLE;
 }