Move pdp_get_peer_ipv() to lib/util.*

Preparation for next commit, where this function will be needed inside
libmisc (lib/*).

Change-Id: Ibab4f6c09d1e5f0e9cfaea28ae1e7ab5b5c219b5
diff --git a/lib/Makefile.am b/lib/Makefile.am
index b6e7aba..533d777 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -1,10 +1,10 @@
 noinst_LIBRARIES = libmisc.a
 
-noinst_HEADERS = gnugetopt.h ippool.h lookup.h syserr.h tun.h in46_addr.h netdev.h gtp-kernel.h
+noinst_HEADERS = gnugetopt.h ippool.h lookup.h syserr.h tun.h in46_addr.h netdev.h gtp-kernel.h util.h
 
 AM_CFLAGS = -O2 -fno-builtin -Wall -DSBINDIR='"$(sbindir)"' -ggdb $(LIBOSMOCORE_CFLAGS)
 
-libmisc_a_SOURCES = getopt1.c getopt.c ippool.c lookup.c tun.c debug.c in46_addr.c netdev.c
+libmisc_a_SOURCES = getopt1.c getopt.c ippool.c lookup.c tun.c debug.c in46_addr.c netdev.c util.c
 
 if ENABLE_GTP_KERNEL
 AM_CFLAGS += -DGTP_KERNEL $(LIBGTPNL_CFLAGS)