coding: Add BER-reporting RACH decode functions

For all other decode operations we report the BER, but not for the
RACH.  This results in osmo-bts-trx not being able to report BER
to the higher layers, which is possible on other BTS backends.

Let's close this gap by introducing gsm0503_rach_ext_decode_ber()
and gsm0503_rach_decode_ber() with the usual n_errors / n_bits_total
arguments.

Change-Id: I2b1926a37bde860dcfeb0d613eb55a71271928c5
diff --git a/tests/coding/coding_test.c b/tests/coding/coding_test.c
index 660f51f..7b4f2a5 100644
--- a/tests/coding/coding_test.c
+++ b/tests/coding/coding_test.c
@@ -123,7 +123,7 @@
 	memset(bursts_s + 6, 0, 8);
 
 	/* Decode, correcting errors */
-	gsm0503_rach_decode(&result, bursts_s, bsic);
+	gsm0503_rach_decode_ber(&result, bursts_s, bsic, NULL, NULL);
 	printf("Decoded: %02x\n", result);
 
 	if (ra != result)
@@ -153,7 +153,7 @@
 	memset(bursts_s + 9, 0, 8);
 
 	/* Decode, correcting errors */
-	gsm0503_rach_ext_decode(&result, bursts_s, bsic);
+	gsm0503_rach_ext_decode_ber(&result, bursts_s, bsic, NULL, NULL);
 	printf("Decoded: %02x\n", result);
 
 	if (ra != result)