Fixed MSVC compilation warning introduced by ticket #1046


git-svn-id: https://svn.pjsip.org/repos/pjproject/trunk@3124 74dad513-b988-da41-8d7b-12977e46ad98
diff --git a/pjlib/src/pj/sock_common.c b/pjlib/src/pj/sock_common.c
index 4a1e795..ec649e6 100644
--- a/pjlib/src/pj/sock_common.c
+++ b/pjlib/src/pj/sock_common.c
@@ -900,7 +900,7 @@
 		    unsigned k;
 
 		    for (k=0; k<16; ++k) {
-			am[k] = (a[k] & pm[k]) & 0xFF;
+			am[k] = (pj_uint8_t)((a[k] & pm[k]) & 0xFF);
 		    }
 
 		    if (pj_memcmp(am, pa, 16)==0) {