[ELF] - Linkerscript: accept space between '=' and expression in section filler.

Previously we failed to parse next scripts because disallowed
a space between filler value and '=':

  .text : {
...
  } :text = 0x9090

Differential revision: https://reviews.llvm.org/D24831

llvm-svn: 282248
diff --git a/lld/ELF/LinkerScript.cpp b/lld/ELF/LinkerScript.cpp
index 0febb25..646dbbd 100644
--- a/lld/ELF/LinkerScript.cpp
+++ b/lld/ELF/LinkerScript.cpp
@@ -1275,8 +1275,12 @@
       setError("unknown command " + Tok);
   }
   Cmd->Phdrs = readOutputSectionPhdrs();
-  if (peek().startswith("="))
+
+  if (skip("="))
+    Cmd->Filler = readOutputSectionFiller(next());
+  else if (peek().startswith("="))
     Cmd->Filler = readOutputSectionFiller(next().drop_front());
+
   return Cmd;
 }