Add function to set Sa bits to common part

Change-Id: I4f5f975f0e5f708ae573a1e1ce41c6a08c207fad
diff --git a/src/e1_input.c b/src/e1_input.c
index a7313dd..2d10513 100644
--- a/src/e1_input.c
+++ b/src/e1_input.c
@@ -455,6 +455,16 @@
 	return 0;
 }
 
+int e1inp_ts_set_sa_bits(struct e1inp_line *line, uint8_t sa_bits)
+{
+	struct e1inp_driver *driver;
+
+	driver = line->driver;
+	if (!driver->set_sa_bits)
+		return -ENOTSUP;
+	return driver->set_sa_bits(line, sa_bits);
+}
+
 static int e1inp_line_use_cb(struct osmo_use_count_entry *use_count_entry, int32_t old_use_count,
 			     const char *file, int file_line)
 {