DAP: Only write to the ABORT register after doing the read.

We were seeing reads failing before this change. Additionally scoping the
SWD bus whilst using a Segger SWD debugger had aborts after the read and
not before.

src/libswd_dap.c

@@ -607,15 +607,15 @@ int libswd_ap_read(libswd_ctx_t *libswdctx, libswd_operation_t operation, char a
    }
    if (retry==0) return LIBSWD_ERROR_MAXRETRY;
   }
-  // Clear all posisble error flags that may remain, but don't abort transaction.
-  abort=0xFFFFFFFE;
-  res=libswd_dap_errors_handle(libswdctx, LIBSWD_OPERATION_EXECUTE, &abort, &ctrlstat); 
-  if (res<0) return res; 
   res=libswd_dp_read(libswdctx, LIBSWD_OPERATION_EXECUTE, LIBSWD_DP_RDBUFF_ADDR, data);
   if (res<0) {
    libswd_log(libswdctx, LIBSWD_LOGLEVEL_ERROR, "LIBSWD_E: libswd_ap_read(libswdctx=@%p, operation=%s, addr=0x%X, **data=0x%X/%s) failed: %s.\n", (void*)libswdctx, libswd_operation_string(operation), addr, **data, libswd_bin32_string(*data), libswd_error_string(res));
    return res;
   }
+  // Clear all possible error flags that may remain, but don't abort transaction.
+  abort=0xFFFFFFFE;
+  res=libswd_dap_errors_handle(libswdctx, LIBSWD_OPERATION_EXECUTE, &abort, &ctrlstat);
+  if (res<0) return res;
   libswd_log(libswdctx, LIBSWD_LOGLEVEL_DEBUG, "LIBSWD_D: libswd_ap_read(libswdctx=@%p, command=%s, addr=0x%X, **data=0x%X/%s) execution OK.\n", (void*)libswdctx, libswd_operation_string(operation), addr, **data, libswd_bin32_string(*data));
   return cmdcnt;
  } else return LIBSWD_ERROR_BADOPCODE;