Do not handle DefinedCommon in linker scripts.
Do not handle DefinedCommon in linker scripts.

Because of r314495, DefinedCommon symbols cannot reach to
getSymbolValue function. When they reach the fucntion, they have
already been converted to DefinedRegular symbols.

git-svn-id: f6089bf0e6284f307027cef4f64114ee9ebb0424@315432 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/lld,llvm-mirror/lld