run_lto_binutils_test: Pass $plug_opt to nm

Pass $plug_opt to nm when setting dump_prog to nm to load plugin.

	PR binutils/21479
	* testsuite/ld-plugin/lto-binutils.exp (run_lto_binutils_test):
	Pass $plug_opt to nm.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>

ld/testsuite/ld-plugin/lto-binutils.exp

diff --git a/ld/testsuite/ld-plugin/lto-binutils.exp b/ld/testsuite/ld-plugin/lto-binutils.exp
index de017f0..4970e22 100644
--- a/ld/testsuite/ld-plugin/lto-binutils.exp
+++ b/ld/testsuite/ld-plugin/lto-binutils.exp
@@ -125,7 +125,7 @@
 		    objdump
 			{ set dump_prog $objdump }
 		    nm
-			{ set dump_prog $nm }
+			{ set dump_prog "$nm $plug_opt" }
 		    readelf
 			{ set dump_prog $READELF }
 		    default