gsm48_rest_octets: fix wrong value

The compiler complains:

gsm48_rest_octets.c:79:11: warning: initializer overrides prior
initialization of this subobject [-Winitializer-overrides]
   79 |         [0x08] = {2,  2},
      |                  ^~~~~~~
gsm48_rest_octets.c:78:11: note: previous initialization is here
   78 |         [0x08] = {2,  1},
      |                  ^~~~~~~

And a quick look at 04.18 confirms:

0 1 0 0 0	2	1
0 1 0 0 1	2	2

Change-Id: I672e2ce53fd07157d15fec350cfbe32a19a52941
diff --git a/src/gsm/gsm48_rest_octets.c b/src/gsm/gsm48_rest_octets.c
index b63c63f..57c2c99 100644
--- a/src/gsm/gsm48_rest_octets.c
+++ b/src/gsm/gsm48_rest_octets.c
@@ -76,7 +76,7 @@
 
 	[0x07] = {2,  0},
 	[0x08] = {2,  1},
-	[0x08] = {2,  2},
+	[0x09] = {2,  2},
 	[0x0a] = {2,  3},
 	[0x0b] = {2,  4},
 	[0x0c] = {2,  5},