libdl: fix unused variable warning

The following warning introduced with commit 231e4a9b4 (libdl: fix dlopen
implementation from statically linked application):

ldso/libdl/libdl.c: In function 'do_dlopen':
ldso/libdl/libdl.c:311:23: warning: unused variable 'ls' [-Wunused-variable]

Cc: Filippo Arcidiacono <filippo.arcidiacono@st.com>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

ldso/libdl/libdl.c

@@ -308,7 +308,9 @@ static void *do_dlopen(const char *libname, int flag, ElfW(Addr) from)
 	struct elf_resolve **init_fini_list;
 	static bool _dl_init;
 	struct elf_resolve **local_scope;
+#ifdef SHARED
 	struct r_scope_elem *ls;
+#endif
 #if defined(USE_TLS) && USE_TLS
 	bool any_tls = false;
 #endif