Fix EGPRS DL window calculation during tbf update

Earlier there was no handling for recalculation of DL window
size during tbf update. Which has been fixed in this patch.

Related: OS#1808
Change-Id: I41aa807068520460fd665a55e3529e60f6bbb630
diff --git a/tests/tbf/TbfTest.err b/tests/tbf/TbfTest.err
index 90f04be..0c9c877 100644
--- a/tests/tbf/TbfTest.err
+++ b/tests/tbf/TbfTest.err
@@ -6400,7 +6400,8 @@
 PDCH(TS 4, TRX 0): Attaching TBF(TFI=0 TLLI=0x00000000 DIR=DL STATE=NULL EGPRS), 1 TBFs, USFs = 00, TFIs = 00000001.
 - Assigning DL TS 5
 PDCH(TS 5, TRX 0): Attaching TBF(TFI=0 TLLI=0x00000000 DIR=DL STATE=NULL EGPRS), 1 TBFs, USFs = 00, TFIs = 00000001.
-DL TBF slots: 0x3c, N: 4, WS: 192
+TBF(TFI=0 TLLI=0x00000000 DIR=DL STATE=NULL EGPRS): Setting EGPRS window size to 384
+DL TBF slots: 0x3c, N: 4, WS: 384
 TBF(TFI=0 TLLI=0x00000000 DIR=DL STATE=NULL EGPRS) changes state from NULL to RELEASING
 TBF(TFI=0 TLLI=0x00000000 DIR=DL STATE=RELEASING EGPRS) free
 PDCH(TS 2, TRX 0): Detaching TBF(TFI=0 TLLI=0x00000000 DIR=DL STATE=RELEASING EGPRS), 0 TBFs, USFs = 00, TFIs = 00000000.