Deprecate comp128

Mark function as deprecated to discourage its usage: people should use
generic API in osmocom/crypt/auth.h
diff --git a/src/gsm/comp128.c b/src/gsm/comp128.c
index b7a2382..abb4917 100644
--- a/src/gsm/comp128.c
+++ b/src/gsm/comp128.c
@@ -185,7 +185,7 @@
 }
 
 void
-comp128(const uint8_t *ki, const uint8_t *rand, uint8_t *sres, uint8_t *kc)
+comp128v1(const uint8_t *ki, const uint8_t *rand, uint8_t *sres, uint8_t *kc)
 {
 	int i;
 	uint8_t x[32], bits[128];
@@ -228,3 +228,8 @@
 	kc[7] = 0;
 }
 
+void
+comp128(const uint8_t *ki, const uint8_t *rand, uint8_t *sres, uint8_t *kc)
+{
+    comp128v1(ki, rand, sres, kc);
+}