soft_uart: cosmetic: use consistent naming for the Rx buffer msgb

In osmo_soft_uart_flush_rx() we use "soft_uart_rx", so be consistent.

Change-Id: Id637a39bab8ecd04bca5580bb48f965b501f5b2e
diff --git a/src/core/soft_uart.c b/src/core/soft_uart.c
index 6cc8ab4..c6a6dbd 100644
--- a/src/core/soft_uart.c
+++ b/src/core/soft_uart.c
@@ -492,7 +492,7 @@
 		suart->rx.flow_state = SUART_FLOW_ST_IDLE;
 	} else if (enable && !suart->rx.running) {
 		if (!suart->rx.msg)
-			suart->rx.msg = msgb_alloc_c(suart, suart->cfg.rx_buf_size, "soft_uart rx");
+			suart->rx.msg = msgb_alloc_c(suart, suart->cfg.rx_buf_size, "soft_uart_rx");
 		suart->rx.running = true;
 		suart->rx.flow_state = SUART_FLOW_ST_IDLE;
 	}