geoip: fix compiler warning

detect-geoip.c:78:40: error: incompatible pointer types assigning to 'int (*)(ThreadVars *, DetectEngineThreadCtx *, Packet *, const Signature *, const SigMatchCtx *)' from 'int (ThreadVars *, DetectEngineThreadCtx *, Packet *, Signature *, const SigMatchCtx *)' [-Werror,-Wincompatible-pointer-types]
    sigmatch_table[DETECT_GEOIP].Match = DetectGeoipMatch;
                                       ^ ~~~~~~~~~~~~~~~~
1 error generated.

Bug #2045

src/detect-geoip.c

@@ -63,7 +63,7 @@ void DetectGeoipRegister(void)
 
 
 static int DetectGeoipMatch(ThreadVars *, DetectEngineThreadCtx *, Packet *,
-                             Signature *, const SigMatchCtx *);
+                            const Signature *, const SigMatchCtx *);
 static int DetectGeoipSetup(DetectEngineCtx *, Signature *, char *);
 static void DetectGeoipRegisterTests(void);
 static void DetectGeoipDataFree(void *);
@@ -165,7 +165,7 @@ static int CheckGeoMatchIPv4(const DetectGeoipData *geoipdata, uint32_t ip)
  * \retval 1 match
  */
 static int DetectGeoipMatch(ThreadVars *t, DetectEngineThreadCtx *det_ctx,
-                             Packet *p, Signature *s, const SigMatchCtx *ctx)
+                            Packet *p, const Signature *s, const SigMatchCtx *ctx)
 {
     const DetectGeoipData *geoipdata = (const DetectGeoipData *)ctx;
     int matches = 0;