[GOLD] Don't assert in powerpc stub_table

A branch in a non-exec section that needs a stub can lead to this
assertion.

	* powerpc.cc (Powerpc_relobj::stub_table): Return NULL rather
	then asserting.

gold/ChangeLog

diff --git a/gold/ChangeLog b/gold/ChangeLog
index 1fe7d03..65c6277 100644
--- a/gold/ChangeLog
+++ b/gold/ChangeLog
@@ -2,6 +2,10 @@
 
 	Apply from master
 	2016-12-08  Alan Modra  <amodra@gmail.com>
+	* powerpc.cc (Powerpc_relobj::stub_table): Return NULL rather
+	then asserting.
+
+	2016-12-08  Alan Modra  <amodra@gmail.com>
 	* options.h (--stub-group-multi): Fix typo.
 
 	2016-12-07  Alan Modra  <amodra@gmail.com>

gold/powerpc.cc

diff --git a/gold/powerpc.cc b/gold/powerpc.cc
index 7d4a384..4d9e669 100644
--- a/gold/powerpc.cc
+++ b/gold/powerpc.cc
@@ -292,8 +292,8 @@
 	  = static_cast<Target_powerpc<size, big_endian>*>(
 	      parameters->sized_target<size, big_endian>());
 	unsigned int indx = this->stub_table_index_[shndx];
-	gold_assert(indx < target->stub_tables().size());
-	return target->stub_tables()[indx];
+	if (indx < target->stub_tables().size())
+	  return target->stub_tables()[indx];
       }
     return NULL;
   }