Ignore -no-keep-memory.

When the -no-keep-memory option is given, BFD linker tries to save
memory in their own way. Since our internal architecture is completely
different from that linker, that option doesn't make sense to us.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@301772 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/ELF/Options.td b/ELF/Options.td
index cf2045b..8863912 100644
--- a/ELF/Options.td
+++ b/ELF/Options.td
@@ -385,6 +385,7 @@
 def no_allow_shlib_undefined: F<"no-allow-shlib-undefined">;
 def no_copy_dt_needed_entries: F<"no-copy-dt-needed-entries">,
   Alias<no_add_needed>;
+def no_keep_memory: F<"no-keep-memory">;
 def no_mmap_output_file: F<"no-mmap-output-file">;
 def no_warn_common: F<"no-warn-common">;
 def no_warn_mismatch: F<"no-warn-mismatch">;