utils: fix dec_xplmn_w_act() and format_xplmn_w_act()

The function dec_xplmn_w_act(), which is also used by
format_xplmn_w_act() is using integer numbers as MCC/MNC representation.
This causes various problems since the information about leading zeros
gets lost.

Change-Id: I57f7dff80f48071ef9a3732ae1088882b127a6d4
diff --git a/pysim-testdata/sysmoISIM-SJA2.ok b/pysim-testdata/sysmoISIM-SJA2.ok
index d95387b..c463c3f 100644
--- a/pysim-testdata/sysmoISIM-SJA2.ok
+++ b/pysim-testdata/sysmoISIM-SJA2.ok
@@ -11,7 +11,7 @@
 Display OPLMN: True
 PLMNsel: 00f110ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
 PLMNwAcT:
-	00f110ffff # MCC: 001 MNC: 001 AcT: UTRAN, E-UTRAN, GSM, GSM COMPACT, cdma2000 HRPD, cdma2000 1xRTT
+	00f110ffff # MCC: 001 MNC: 01 AcT: UTRAN, E-UTRAN, GSM, GSM COMPACT, cdma2000 HRPD, cdma2000 1xRTT
 	ffffff0000 # unused
 	ffffff0000 # unused
 	ffffff0000 # unused
@@ -25,7 +25,7 @@
 	ffffff0000 # unused
 
 OPLMNwAcT:
-	00f110ffff # MCC: 001 MNC: 001 AcT: UTRAN, E-UTRAN, GSM, GSM COMPACT, cdma2000 HRPD, cdma2000 1xRTT
+	00f110ffff # MCC: 001 MNC: 01 AcT: UTRAN, E-UTRAN, GSM, GSM COMPACT, cdma2000 HRPD, cdma2000 1xRTT
 	ffffff0000 # unused
 	ffffff0000 # unused
 	ffffff0000 # unused
@@ -39,7 +39,7 @@
 	ffffff0000 # unused
 
 HPLMNAcT:
-	00f110ffff # MCC: 001 MNC: 001 AcT: UTRAN, E-UTRAN, GSM, GSM COMPACT, cdma2000 HRPD, cdma2000 1xRTT
+	00f110ffff # MCC: 001 MNC: 01 AcT: UTRAN, E-UTRAN, GSM, GSM COMPACT, cdma2000 HRPD, cdma2000 1xRTT
 	ffffff0000 # unused
 	ffffff0000 # unused
 	ffffff0000 # unused