Use GSM48_MT_RR_IMM_ASS instead of hardcoded 0x3f value

Change-Id: Id966cbab403763d006bd5e59757c5bf57402bf9d
diff --git a/src/encoding.cpp b/src/encoding.cpp
index c24d187..67defec 100644
--- a/src/encoding.cpp
+++ b/src/encoding.cpp
@@ -447,7 +447,7 @@
 
 	bitvec_write_field(dest, &wp, 0x0, 4);  // Skip Indicator
 	bitvec_write_field(dest, &wp, 0x6, 4);  // Protocol Discriminator
-	bitvec_write_field(dest, &wp, 0x3F, 8); // Immediate Assignment Message Type
+	bitvec_write_field(dest, &wp, GSM48_MT_RR_IMM_ASS, 8); // Immediate Assignment Message Type
 
 	// 10.5.2.25b Dedicated mode or TBF
 	bitvec_write_field(dest, &wp, 0x0, 1);      // spare
diff --git a/src/pcu_l1_if.cpp b/src/pcu_l1_if.cpp
index 67e4de5..f964b78 100644
--- a/src/pcu_l1_if.cpp
+++ b/src/pcu_l1_if.cpp
@@ -510,7 +510,7 @@
 
 	switch (data_cnf->sapi) {
 	case PCU_IF_SAPI_PCH:
-		if (data_cnf->data[2] == 0x3f)
+		if (data_cnf->data[2] == GSM48_MT_RR_IMM_ASS)
 			bts_rcv_imm_ass_cnf(bts, data_cnf->data, data_cnf->fn);
 		break;
 	default: