gprs_gmm.c: Flag mmctx_set_(p)mm_state() functions static

Change-Id: I061144b6994ee40d5b32eb321dd4f3d3786d028d
diff --git a/src/gprs/gprs_gmm.c b/src/gprs/gprs_gmm.c
index bb0e002..e1bed0d 100644
--- a/src/gprs/gprs_gmm.c
+++ b/src/gprs/gprs_gmm.c
@@ -136,7 +136,7 @@
 	}
 }
 
-void mmctx_set_pmm_state(struct sgsn_mm_ctx *ctx, enum gprs_pmm_state state)
+static void mmctx_set_pmm_state(struct sgsn_mm_ctx *ctx, enum gprs_pmm_state state)
 {
 	if (ctx->ran_type != MM_CTX_T_UTRAN_Iu)
 		return;
@@ -162,7 +162,7 @@
 	ctx->pmm_state = state;
 }
 
-void mmctx_set_mm_state(struct sgsn_mm_ctx *ctx, enum gprs_pmm_state state)
+static void mmctx_set_mm_state(struct sgsn_mm_ctx *ctx, enum gprs_pmm_state state)
 {
 	if (ctx->ran_type != MM_CTX_T_GERAN_Gb)
 		return;