tns: Change 2.5ms 48KHz TNS division, as HR specification and reference implementation

src/tns.c

diff --git a/src/tns.c b/src/tns.c
index e809203..e3fc3b7 100644
--- a/src/tns.c
+++ b/src/tns.c
@@ -67,7 +67,7 @@
     static const int sub_2m5_wb[]   = {  3,  20,  40 };
     static const int sub_2m5_sswb[] = {  3,  30,  60 };
     static const int sub_2m5_swb[]  = {  3,  40,  80 };
-    static const int sub_2m5_fb[]   = {  3,  50, 100 };
+    static const int sub_2m5_fb[]   = {  3,  51, 100 };
 
     static const int sub_5m_nb[]    = {  6,  23,  40 };
     static const int sub_5m_wb[]    = {  6,  43,  80 };

test/tns.py

diff --git a/test/tns.py b/test/tns.py
index 01f1f6f..7a28320 100644
--- a/test/tns.py
+++ b/test/tns.py
@@ -26,7 +26,7 @@
     SUB_LIM_2M5_WB   = [ [   3,  20,  40  ] ]
     SUB_LIM_2M5_SSWB = [ [   3,  30,  60  ] ]
     SUB_LIM_2M5_SWB  = [ [   3,  40,  80  ] ]
-    SUB_LIM_2M5_FB   = [ [   3,  50, 100  ] ]
+    SUB_LIM_2M5_FB   = [ [   3,  51, 100  ] ]
 
     SUB_LIM_2M5 = [
         SUB_LIM_2M5_NB , SUB_LIM_2M5_WB, SUB_LIM_2M5_SSWB,